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Thread pitch..
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No.
But if you take one to a Lowe's, or a Home Depot, they usually have a thread matching card or device and you can >carefully< try your screw and find the right thread and pitch. Ask for help if you need to, but remember, the help you get may know less than you do and might screw up your screw. And that you don't wanna do. |
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开云体育Thanks.. But I can’t do that as the guidescope is mounted and aligned.. There is NO WAY I am removing one of these screws now.. I had expected to find the right PDF from Losmandy – they are very good at having all patterns somewhere – but haven’t.. I did find some Vixen rails with 5/16 – 16 holes in them.. 99% sure that’s the guidescope adjustment screw size also, so I *will* go buy some from ACE.. And some drill bits.. Some painter’s tape.. etc.. ? No idea how to countersink a hole so the bottom is flat and not conical so the bottom of the cap screw has a place to land, but that might become apparent when I am standing in the store eyeballing the drill bit section.. ? Maybe.. ? Derek ? ? From: [email protected] [mailto:[email protected]] On Behalf Of sonnyedmonds@...
Sent: Wednesday, January 01, 2020 12:39 PM To: [email protected] Subject: Re: [Losmandy_users_io] Thread pitch.. ? No. |
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开云体育Derek, ? Remove just one screw, noting the tension with a precise instrument – the human hand. Then take it to a DIY or Ace store as suggested by one of our other friends. When you get back to the mount insert that one screw in the ring and tension it as much as you had before. ? Since the other two screws in that ring (not to mention the three in the other ring) weren’t changed the boresight (to use the proper artillery term) of the guidescope won’t have changed significantly. ? The difference in boresight alignment (main vs. guidescope) will be trivial, unless you are trying to keep things within arc seconds. I know of no reason worry about that unless you are shooting very long exposures with poor polar alignment. ? Besides, why do you care about the thread if you are unwilling to remove one? ? Mark Christensen |
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开云体育Besides, why do you care about the thread if you are unwilling to remove one? *** Because I want to put more bolts into the existing “extra holes” to add a Vixen rail.. But yes, I will try your suggestion and remove one from the middle ring.. If my focuser and extension tubes are tight, it should stay put.. Nice idea, Thanks! ? Derek ? From: [email protected] [mailto:[email protected]] On Behalf Of Mark Christensen
Sent: Wednesday, January 01, 2020 10:13 PM To: [email protected] Subject: Re: [Losmandy_users_io] Thread pitch.. ? Derek, ? Remove just one screw, noting the tension with a precise instrument – the human hand. Then take it to a DIY or Ace store as suggested by one of our other friends. When you get back to the mount insert that one screw in the ring and tension it as much as you had before. ? Since the other two screws in that ring (not to mention the three in the other ring) weren’t changed the boresight (to use the proper artillery term) of the guidescope won’t have changed significantly. ? The difference in boresight alignment (main vs. guidescope) will be trivial, unless you are trying to keep things within arc seconds. I know of no reason worry about that unless you are shooting very long exposures with poor polar alignment. ? Besides, why do you care about the thread if you are unwilling to remove one? ? Mark Christensen |
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Derek where do you want to add a rail - on top of the guidescope rings? On Thu, Jan 2, 2020 at 8:12 AM Derek C Breit <breit_ideas@...> wrote:
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Brian? Brian Valente portfolio |
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开云体育Maybe, though I don’t think the Losmandy adapter will fit there so I think it has to go in a different set of holes.. If you look at the guidescope rings, the image shows 4 sets of adjustment screws.. It is also drilled to use only three sets.. So there are seven adjustment holes that are all the same size.. Once the rail is on, I would be attaching the adapter.. The adapter is the same as the base of the guidescope rings.. i.e. remove the rings and what is left is the adapter.. ? Probably will have to use the “side” holes.. Let’s see if I can attach an image in this group.. The empty “side” holes are easily seen.. ? Derek ? From: [email protected] [mailto:[email protected]] On Behalf Of Brian Valente
Sent: Thursday, January 02, 2020 8:21 AM To: [email protected] Subject: Re: [Losmandy_users_io] Thread pitch.. ? Derek where do you want to add a rail - on top of the guidescope rings? ? On Thu, Jan 2, 2020 at 8:12 AM Derek C Breit <breit_ideas@...> wrote:
? -- Brian? ? ? ? Brian Valente portfolio |
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开云体育Well now I’m curious on what you plan to do with this plate ? I avoid rings like the plague for anything but a finder scope because they are so prone to flexure and movement through the night that for me they really make for poor guiding. If that is your guidescope and you are adding more stuff to those rings? Sounds like trouble brewing. ? You might consider more of a clamshell type of mount for your guidescope? Prime luce has something like that I used on my tak sky90 and it holds everything really nicely ? Brian ? From: [email protected] [mailto:[email protected]] On Behalf Of Derek C Breit
Sent: Thursday, January 2, 2020 3:26 PM To: [email protected] Subject: Re: [Losmandy_users_io] Thread pitch.. ? Maybe, though I don’t think the Losmandy adapter will fit there so I think it has to go in a different set of holes.. If you look at the guidescope rings, the image shows 4 sets of adjustment screws.. It is also drilled to use only three sets.. So there are seven adjustment holes that are all the same size.. Once the rail is on, I would be attaching the adapter.. The adapter is the same as the base of the guidescope rings.. i.e. remove the rings and what is left is the adapter.. ? Probably will have to use the “side” holes.. Let’s see if I can attach an image in this group.. The empty “side” holes are easily seen.. ? Derek ? From: [email protected] [mailto:[email protected]] On Behalf Of Brian Valente ? Derek where do you want to add a rail - on top of the guidescope rings? ? On Thu, Jan 2, 2020 at 8:12 AM Derek C Breit <breit_ideas@...> wrote:
? -- Brian? ? ? ? Brian Valente portfolio |
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开云体育Yes, that’s my guidescope.. I am aware it may not work, but it better because if I have to go to an off axis guider, I would have to also replace my filter wheel and filters too.. None of them are the “thin” variety and I cannot reach focus in the Raptor.. The goal is to mount my ADM Laser Finder.. My camera chips are small and sometimes an object lands outside the FOV, so I just reach up and switch on the laser and I can see which way I need to move.. I also *really* want the two scopes to be on the same object so I can easily swap cameras, so I don’t want a clamshell.. ??? But it may not work at all.. First I have to make it guide at all.. On my Dec axis, the PHD Guiding assistant shows a LARGE time lag when I switch directions AND all the data points it shows on that window are double points.. I am aware of all the different ways to deal with the Dec.. Guide in one direction only.. Don’t guide in Dec at all, etc.. Just got to try it and address the issues as they appear.. I am not very hopeful it’ll work, and certainly not the way I want it to, as I am not doing wide field with a large chip.. ??? We shall see.. ? Derek ? From: [email protected] [mailto:[email protected]] On Behalf Of Brian Valente
Sent: Thursday, January 02, 2020 3:35 PM To: [email protected] Subject: Re: [Losmandy_users_io] Thread pitch.. ? Well now I’m curious on what you plan to do with this plate ? I avoid rings like the plague for anything but a finder scope because they are so prone to flexure and movement through the night that for me they really make for poor guiding. If that is your guidescope and you are adding more stuff to those rings? Sounds like trouble brewing. ? You might consider more of a clamshell type of mount for your guidescope? Prime luce has something like that I used on my tak sky90 and it holds everything really nicely ? Brian ? From: [email protected] [mailto:[email protected]] On Behalf Of Derek C Breit ? Maybe, though I don’t think the Losmandy adapter will fit there so I think it has to go in a different set of holes.. If you look at the guidescope rings, the image shows 4 sets of adjustment screws.. It is also drilled to use only three sets.. So there are seven adjustment holes that are all the same size.. Once the rail is on, I would be attaching the adapter.. The adapter is the same as the base of the guidescope rings.. i.e. remove the rings and what is left is the adapter.. ? Probably will have to use the “side” holes.. Let’s see if I can attach an image in this group.. The empty “side” holes are easily seen.. ? Derek ? From: [email protected] [mailto:[email protected]] On Behalf Of Brian
Valente ? Derek where do you want to add a rail - on top of the guidescope rings? ? On Thu, Jan 2, 2020 at 8:12 AM Derek C Breit <breit_ideas@...> wrote:
? -- Brian? ? ? ? Brian Valente portfolio |
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Hi Ya, Derek,
As a side note here, I suffered along for a time with my guide scope and my Main telescope being "close" but missing the target. I finally decided enough was enough, and centered Polaris in my main tube. Then tweaked and adjusted my Guide Scope camera's picture in PHD2 to be centered with the aim of the Main Tube. I've done a few tweaking's along the way, but they run very close to being parallel. It has made running alignments much easier than using "Kentucky Windage". Just a matter of taking some time for dialing in your two scopes. Even if you are Guided Visual. |
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开云体育Are you talking about making a guide scope that is not intended on being “adjustable” point at the same spot as the main scope, where I might have to shim or file or generally fiddle with the mounting of the guidescope to collimate it?? Yep, I may have to do that, though it is more likely that if my setup now exhibits flexure, then I will either A) go to an OAG w/ new filter wheel and filters, or B) give up on the idea of guiding at all.. As soon as “imaging” becomes “difficult”, I wont be doing it anymore, as I never wanted to image because I don’t want to “do the work”.. I started planetary imaging because it requires no guiding.. That has worked perfectly for me (and my perfect optics help a great deal with that!) as the processing I do is very simple – taking just a few mouse clicks and doing it identical for all the different planets I have imaged.. Therefore it doesn’t take any work.. I can uncover the scope, take multiple videos of multiple planets, stack and process the results, and be in bed at a reasonable hour for work the next day.. MY NEW GOAL is simply to do “More”, but the targets require longer exposures and guiding.. If the Weather would cooperate, I would be out imaging Venus (as soon as the Sun set), then Neptune, and Uranus.. My next thought, like it has been for many months now, is “NOW WHAT??” Small DSO’s, such as small planetaries, seem like what I should be able to do.. Double Stars.. Stuff the scope is already setup for.. Additionally, this makes / leaves my setup modular.. I can just pull out a camera and drop in an ocular and I wont have to reengineer the entire setup (for instance), but it does remain to be seen if it works at all.. I acquired the three ring guidexcope setup because SOMEONE in this group – who shall remain nameless - said how great it worked.. Now that I have it, everyone is telling me “No!”, and the person I was emulating uses a different method now too.. :-// It *is* all assembled, aligned, and ready to test out if and when the weather falls in line.. If it doesn’t work as I want it to, switching boats in the middle of the rapids will be exciting.. ? Derek ? From: [email protected] [mailto:[email protected]] On Behalf Of sonnyedmonds@...
Sent: Saturday, January 04, 2020 12:35 PM To: [email protected] Subject: Re: [Losmandy_users_io] Thread pitch.. ? Hi Ya, Derek, |
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Derek with which camera are you doing imaging now? On Sat, Jan 4, 2020 at 2:42 PM Derek C Breit <breit_ideas@...> wrote:
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Brian? Brian Valente portfolio |
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开云体育Previously I have been doing planets with the ASI178 OSC and IR band with the ASI120 Mono on the 130mm Raptor.. I bought the QHY178M Cool for various single band planetary imaging and higher resolution.. ? This is where I am heading.. Imaging scope.. 130mm Raptor (f/7=910mm) w/ an ASI 178 OSC or the new QHY178 Cool Mono.. Both are 2.4um Pixels.. Around 0.5” per pixel.. Guide Scope.. 80mm Nighthawk (f/6=480mm) w/ an ASI 120 Mono w/ 3.75um Pixels.. Around 1.6” per pixel.. ? I may Barlow the guidescope, but not right off the bat as I know I am asking a lot A) as a beginner, B) with a separate guidescope, and C) at these image scales, but hope springs eternal! ? Derek ? ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Brian Valente
Sent: Saturday, January 04, 2020 7:04 PM To: [email protected] Subject: Re: [Losmandy_users_io] Thread pitch.. ? Derek with which camera are you doing imaging now? ? |
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Derek here's what i'm thinking with the cmos cameras you have, you can employ more?of a planetary approach to imaging DSOs and not sweat the guiding.? just make sure to nail your polar alignment (although i'm a longtime polemaster user, i've come to really like the polar assist in sharpcap 3.2 and it's super inexpensive too), and shoot maybe 30 second exposures. you can go as low as 15 secs.? that way guiding will be less of or no issue for you. i'm a little concerned you are headed down a guiding path that is already pretty rough, and it sounds like it's going to get rougher :) the major downside is you just end up with a ton of data. I've seen folks doing these short exposures on faint objects and when done right it's really spectacular just a thought.... Brian On Sat, Jan 4, 2020 at 8:58 PM Derek C Breit <breit_ideas@...> wrote:
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Brian? Brian Valente portfolio |
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开云体育That is already my fallback position, not guiding at all.. “Less is more”.. “Don’t chase the seeing”.. Doing I like planetary imaging and working slowly to longer and longer exposures is the plan, as I have tweaked things all I can.. Now I need guide logs to see what worked and what didn’t.. I would be pretty pleased with 60 second guiding.. I would be darn near the happiest person alive to have most images useable at 5 minutes though.. I might be close to 60 seconds unguided now, as my PA *was* about 1 minute off and the mount has not been moved.. Since the scope was desaddled and replaced, I am sure it’ll need touching up.. My RA guiding seems darn good already, so there is hope.. Yep, I paid for SharpCap Pro.. I am very ready to try all I have learned in the last 2 months of being mostly off and reading everything I want to know about guiding theory but was afraid to ask.. I just need the WX to cooperate.. It is messing with me now, listing the evenings when I don’t have to work the next day as cloudy.. WAAA.. ? “Imaging – So simple even Derek can do it!” *will* be a slogan someday.. And Y’All will be to blame.. :-)) ? Derek ? From: [email protected] [mailto:[email protected]] On Behalf Of Brian Valente
Sent: Saturday, January 04, 2020 9:18 PM To: [email protected] Subject: Re: [Losmandy_users_io] Thread pitch.. ? Derek here's what i'm thinking ? with the cmos cameras you have, you can employ more?of a planetary approach to imaging DSOs and not sweat the guiding.? ? just make sure to nail your polar alignment (although i'm a longtime polemaster user, i've come to really like the polar assist in sharpcap 3.2 and it's super inexpensive too), and shoot maybe 30 second exposures. you can go as low as 15 secs.? ? that way guiding will be less of or no issue for you. i'm a little concerned you are headed down a guiding path that is already pretty rough, and it sounds like it's going to get rougher :) ? the major downside is you just end up with a ton of data. I've seen folks doing these short exposures on faint objects and when done right it's really spectacular ? just a thought.... ? ? Brian ? On Sat, Jan 4, 2020 at 8:58 PM Derek C Breit <breit_ideas@...> wrote:
? -- Brian? ? ? ? Brian Valente portfolio |
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开云体育Derek, ? Your recent post suggested you have a fear of autoguiding. You shouldn’t be afraid of it. Some try to image without guiding and almost make a fetish of it. I don’t recommend you do that other than with short focal length imaging optics. ? With a modest focal length like 1000 mm or less guiding is easy and doesn’t require anything like a Barlow on the guider as you suggested you would need to do. In fact, at 1000mm focal length for the imaging scope, a 300mm or less guider will be fine. ? And the shorter guide scope focal length will make it easier to find guide stars. ? Why can you get away with a guider with 1/3 to ? of the focal length of the imaging scope? Because autoguider cameras and software can detect errors of the order of 1/10th to ? pixel routinely. ? Another very common mistake is to guide with an expensive, heavy, APO refractors, when a lighter weight (but still rigid) and shorter focal length instrument will work – heavy expensive guidescopes are a waste of money and mass budget. But if it is what you have, and you can live with the weight, go ahead and use it. But you don’t need to Barlow it. ? People often assume that everything has to be absolutely optimal and perfect in this business. That’s OK if you want to set yourself up for unhappiness, esp. since 2 arc second ?long term seeing is very common (which is why planetary imaging now uses video streams and software to pluck out the best frames). I have friends who remotely image from mountains and they cry if they don’t get 1 arc second or better over 10s of minutes. We who live under the air-ocean rarely get to see that. ? I got into this hobby when guiding meant the lucky astronomer had to glue their eyeball to a guide scope eyepiece and push buttons on a hand controller. And individual (film) exposures could be ? hour or more long. Try doing that on a cold winters night – my jeans once froze to the ground while guiding near the zenith. Autoguiding makes that trivial and easy. And cheap compared to everything else. ? My bottom line is that there is no reason not to guide for long exposures given the availability of guide cameras and free software. And it doesn’t require a high-end computer to do it. In fact, the cheaper the better since laptops are generally not built to resist dew and frost – taking a high-end MAC or PC into the field is not necessary or desirable. Put the laptop in a tub and put a silicon keyboard skin on it. ? So don’t be afraid of autoguiding. And like anything else, practice makes perfect. ? Regards, ? Mark Christensen |
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开云体育Hello Mark.. ? I have pretty much come to that conclusion, that it shouldn’t be that hard.. One thing I am fearful of is that I am wrong and that all the people – who actually have done guiding – are right that the way I want to do it wont work.. ??? Yeah, forget I ever mentioned barlowing the guidescope, I wont be doing that.. Many people use an ST80 as a guidescope, and I could use the one I have, but the NightHawk is vastly superior mechanically (much better focuser and can be locked), all connection toward the camera are either threaded or compression ring w/ multiple thumbscrews, and of course two rings hold the scope, and one ring is near the camera.. If any setup is adequately rigid, this one is.. If it is still not good enough, but I am confident it will be, I can go with the ST80 or with the little and very light 60mm f/4 guidescope I already have.. ??? The real fear is that I have to switch to an OAG – because I would have to replace the filter wheel and filters too, but I am trying to push that thought out of my head with exactly what you said.. “It ain’t that hard”.. If I ignore my (currently) excessive Dec Backlash / ignore guiding in Dec at all or just one direction, then it *will* be easy, as my RA guides easily and very well.. ??? The bigger problem is the $%@^&*&# Weather.. Perfectly clear last night, but 30mph winds.. I swear the weather is messing with me now.. ? Derek From: [email protected] [mailto:[email protected]] On Behalf Of Mark Christensen
Sent: Sunday, January 05, 2020 10:16 PM To: [email protected] Subject: Re: [Losmandy_users_io] Thread pitch.. ? Derek, ? Your recent post suggested you have a fear of autoguiding. You shouldn’t be afraid of it. Some try to image without guiding and almost make a fetish of it. I don’t recommend you do that other than with short focal length imaging optics. ? With a modest focal length like 1000 mm or less guiding is easy and doesn’t require anything like a Barlow on the guider as you suggested you would need to do. In fact, at 1000mm focal length for the imaging scope, a 300mm or less guider will be fine. ? And the shorter guide scope focal length will make it easier to find guide stars. ? Why can you get away with a guider with 1/3 to ? of the focal length of the imaging scope? Because autoguider cameras and software can detect errors of the order of 1/10th to ? pixel routinely. ? Another very common mistake is to guide with an expensive, heavy, APO refractors, when a lighter weight (but still rigid) and shorter focal length instrument will work – heavy expensive guidescopes are a waste of money and mass budget. But if it is what you have, and you can live with the weight, go ahead and use it. But you don’t need to Barlow it. ? People often assume that everything has to be absolutely optimal and perfect in this business. That’s OK if you want to set yourself up for unhappiness, esp. since 2 arc second ?long term seeing is very common (which is why planetary imaging now uses video streams and software to pluck out the best frames). I have friends who remotely image from mountains and they cry if they don’t get 1 arc second or better over 10s of minutes. We who live under the air-ocean rarely get to see that. ? I got into this hobby when guiding meant the lucky astronomer had to glue their eyeball to a guide scope eyepiece and push buttons on a hand controller. And individual (film) exposures could be ? hour or more long. Try doing that on a cold winters night – my jeans once froze to the ground while guiding near the zenith. Autoguiding makes that trivial and easy. And cheap compared to everything else. ? My bottom line is that there is no reason not to guide for long exposures given the availability of guide cameras and free software. And it doesn’t require a high-end computer to do it. In fact, the cheaper the better since laptops are generally not built to resist dew and frost – taking a high-end MAC or PC into the field is not necessary or desirable. Put the laptop in a tub and put a silicon keyboard skin on it. ? So don’t be afraid of autoguiding. And like anything else, practice makes perfect. ? Regards, ? Mark Christensen |
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开云体育Derek, you will get it all together, I have been following these threads because I know that my nights of trials and tribulations? will be here soon enough. I am going to start with a small fast APO and a modded DSLR Canon camera everyone says
this is the best of routes to go and when you go bigger aperture the 80mm can move over to a guide scope. but one thing My backup plan is I can spend the night just viewing if al else fails. I've been Lucky down here in Florida, I've been able to get out five
nights sense New Years eve.the last two nights have been crystal clear.? Clear Skies and no wind to you.
Sent from my Galaxy Tab A
-------- Original message --------
From: Derek C Breit <breit_ideas@...>
Date: 1/6/20 11:47 AM (GMT-06:00)
Subject: Re: [Losmandy_users_io] Thread pitch..
Hello Mark.. ? I have pretty much come to that conclusion, that it shouldn’t be that hard.. One thing I am fearful of is that I am wrong and that all the people – who actually have done guiding – are right that the way I want to do it wont work.. ??? Yeah, forget I ever mentioned barlowing the guidescope, I wont be doing that.. Many people use an ST80 as a guidescope, and I could use the one I have, but the NightHawk is vastly superior mechanically (much better focuser and can be locked), all connection toward the camera are either threaded or compression ring w/ multiple thumbscrews, and of course two rings hold the scope, and one ring is near the camera.. If any setup is adequately rigid, this one is.. If it is still not good enough, but I am confident it will be, I can go with the ST80 or with the little and very light 60mm f/4 guidescope I already have.. ??? The real fear is that I have to switch to an OAG – because I would have to replace the filter wheel and filters too, but I am trying to push that thought out of my head with exactly what you said.. “It ain’t that hard”.. If I ignore my (currently) excessive Dec Backlash / ignore guiding in Dec at all or just one direction, then it *will* be easy, as my RA guides easily and very well.. ??? The bigger problem is the $%@^&*&# Weather.. Perfectly clear last night, but 30mph winds.. I swear the weather is messing with me now.. ? Derek From: [email protected] [mailto:[email protected]]
On Behalf Of Mark Christensen ? Derek, ? Your recent post suggested you have a fear of autoguiding. You shouldn’t be afraid of it. Some try to image without guiding and almost make a fetish of it. I don’t recommend you do that other than with short focal length imaging optics. ? With a modest focal length like 1000 mm or less guiding is easy and doesn’t require anything like a Barlow on the guider as you suggested you would need to do. In fact, at 1000mm focal length for the imaging scope, a 300mm or less guider will be fine. ? And the shorter guide scope focal length will make it easier to find guide stars. ? Why can you get away with a guider with 1/3 to ? of the focal length of the imaging scope? Because autoguider cameras and software can detect errors of the order of 1/10th to ? pixel routinely. ? Another very common mistake is to guide with an expensive, heavy, APO refractors, when a lighter weight (but still rigid) and shorter focal length instrument will work – heavy expensive guidescopes are a waste of money and mass budget. But if it is what you have, and you can live with the weight, go ahead and use it. But you don’t need to Barlow it. ? People often assume that everything has to be absolutely optimal and perfect in this business. That’s OK if you want to set yourself up for unhappiness, esp. since 2 arc second ?long term seeing is very common (which is why planetary imaging now uses video streams and software to pluck out the best frames). I have friends who remotely image from mountains and they cry if they don’t get 1 arc second or better over 10s of minutes. We who live under the air-ocean rarely get to see that. ? I got into this hobby when guiding meant the lucky astronomer had to glue their eyeball to a guide scope eyepiece and push buttons on a hand controller. And individual (film) exposures could be ? hour or more long. Try doing that on a cold winters night – my jeans once froze to the ground while guiding near the zenith. Autoguiding makes that trivial and easy. And cheap compared to everything else. ? My bottom line is that there is no reason not to guide for long exposures given the availability of guide cameras and free software. And it doesn’t require a high-end computer to do it. In fact, the cheaper the better since laptops are generally not built to resist dew and frost – taking a high-end MAC or PC into the field is not necessary or desirable. Put the laptop in a tub and put a silicon keyboard skin on it. ? So don’t be afraid of autoguiding. And like anything else, practice makes perfect. ? Regards, ? Mark Christensen |
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开云体育It’s perfect here for tonight, as the wind has died.. It’ll be near freezing in the AM, but I will be asleep long before that.. ? Scope is cooling as we speak.. We shall see how it goes.. :-)) ? Derek ? From: [email protected] [mailto:[email protected]] On Behalf Of Deric Caselli
Sent: Monday, January 06, 2020 12:54 PM To: [email protected] Subject: Re: [Losmandy_users_io] Thread pitch.. ? Derek, you will get it all together, I have been following these threads because I know that my nights of trials and tribulations? will be here soon enough. I am going to start with a small fast APO and a modded DSLR Canon camera everyone says this is the best of routes to go and when you go bigger aperture the 80mm can move over to a guide scope. but one thing My backup plan is I can spend the night just viewing if al else fails. I've been Lucky down here in Florida, I've been able to get out five nights sense New Years eve.the last two nights have been crystal clear.? Clear Skies and no wind to you. ? ? ? Sent from my Galaxy Tab A ? ? ? -------- Original message -------- From: Derek C Breit <breit_ideas@...> Date: 1/6/20 11:47 AM (GMT-06:00) Subject: Re: [Losmandy_users_io] Thread pitch.. ? Hello Mark.. ? I have pretty much come to that conclusion, that it shouldn’t be that hard.. One thing I am fearful of is that I am wrong and that all the people – who actually have done guiding – are right that the way I want to do it wont work.. ??? Yeah, forget I ever mentioned barlowing the guidescope, I wont be doing that.. Many people use an ST80 as a guidescope, and I could use the one I have, but the NightHawk is vastly superior mechanically (much better focuser and can be locked), all connection toward the camera are either threaded or compression ring w/ multiple thumbscrews, and of course two rings hold the scope, and one ring is near the camera.. If any setup is adequately rigid, this one is.. If it is still not good enough, but I am confident it will be, I can go with the ST80 or with the little and very light 60mm f/4 guidescope I already have.. ??? The real fear is that I have to switch to an OAG – because I would have to replace the filter wheel and filters too, but I am trying to push that thought out of my head with exactly what you said.. “It ain’t that hard”.. If I ignore my (currently) excessive Dec Backlash / ignore guiding in Dec at all or just one direction, then it *will* be easy, as my RA guides easily and very well.. ??? The bigger problem is the $%@^&*&# Weather.. Perfectly clear last night, but 30mph winds.. I swear the weather is messing with me now.. ? Derek From: [email protected] [mailto:[email protected]] On Behalf Of Mark Christensen ? Derek, ? Your recent post suggested you have a fear of autoguiding. You shouldn’t be afraid of it. Some try to image without guiding and almost make a fetish of it. I don’t recommend you do that other than with short focal length imaging optics. ? With a modest focal length like 1000 mm or less guiding is easy and doesn’t require anything like a Barlow on the guider as you suggested you would need to do. In fact, at 1000mm focal length for the imaging scope, a 300mm or less guider will be fine. ? And the shorter guide scope focal length will make it easier to find guide stars. ? Why can you get away with a guider with 1/3 to ? of the focal length of the imaging scope? Because autoguider cameras and software can detect errors of the order of 1/10th to ? pixel routinely. ? Another very common mistake is to guide with an expensive, heavy, APO refractors, when a lighter weight (but still rigid) and shorter focal length instrument will work – heavy expensive guidescopes are a waste of money and mass budget. But if it is what you have, and you can live with the weight, go ahead and use it. But you don’t need to Barlow it. ? People often assume that everything has to be absolutely optimal and perfect in this business. That’s OK if you want to set yourself up for unhappiness, esp. since 2 arc second ?long term seeing is very common (which is why planetary imaging now uses video streams and software to pluck out the best frames). I have friends who remotely image from mountains and they cry if they don’t get 1 arc second or better over 10s of minutes. We who live under the air-ocean rarely get to see that. ? I got into this hobby when guiding meant the lucky astronomer had to glue their eyeball to a guide scope eyepiece and push buttons on a hand controller. And individual (film) exposures could be ? hour or more long. Try doing that on a cold winters night – my jeans once froze to the ground while guiding near the zenith. Autoguiding makes that trivial and easy. And cheap compared to everything else. ? My bottom line is that there is no reason not to guide for long exposures given the availability of guide cameras and free software. And it doesn’t require a high-end computer to do it. In fact, the cheaper the better since laptops are generally not built to resist dew and frost – taking a high-end MAC or PC into the field is not necessary or desirable. Put the laptop in a tub and put a silicon keyboard skin on it. ? So don’t be afraid of autoguiding. And like anything else, practice makes perfect. ? Regards, ? Mark Christensen |