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Re: Guide scope (cross post)
"Flickr can be fussy….Try it again" nope. Same msg. Also that link-text?is a bit?defective due to the period between ".com" and "/photos".??That and the omission of http: or www prevents Yahoo from turning?the text?into an active link. Try again.? I want to see your pics. Stan |
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Re: New 11" EdgeHD
Gary Jarrette
开云体育It is number you get from the company that authorizes you to return something. You put it on the box and that starts the return process. Return Merchandise Authorization ? From: C14_EdgeHD@... [mailto:C14_EdgeHD@...]
Sent: Friday, April 15, 2016 7:45 AM To: C14_EdgeHD@... Subject: [C14_EdgeHD] Re: New 11" EdgeHD ? ? what's "RMA"? |
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Re: Guide scope (cross post)
Gary Jarrette
Hey Bob
I was in the trades when I was working and we always said “anyone can make something nice with brand new tight machines” but it takes skill and knowledge to make something with a less than perfect machine. And so it goes with guiding. There is no substitute for skill. I am sure you know how to use your equipment and get some pretty damn good results. I have and Orion Short Tube 80 for guiding I started out with but was using a OSC camera and soon tired of that so I bought a QSI 6832wsg mono camera. It, of course, had the OAG so the switch was natural for me. I do think a wide FOV of the Short Tube 80 is a nice convenience and if you have one of those rigs under the short tube where you can move is side to side and up and down you have no limit to guide stars of your choice so there are advantages there for sure. I will revisit the short tube even if it is just to put a video camera on it. While on the subject my good friend and mentor Parijat is using Meta Guide to do some video guiding and I must say the results are astounding. I think more people should investigate this method of guiding and he is using a QHY 5-II. Meta Guide can take ten short guide exposures per second, select the best 5 then average the centroid then make a correction. You can also watch, in real time, the star and get an arcsec/pix readout on the fly so you can actually watch seeing change per guide move or even less. I have never seen so many 1.3 and 1.4 arcsec/pixel round stars in his photos and he lives in a light polluted area. Believe me my area is twice as dark as his but his guiding is mind blowing.This is something to be explored. Take care and kudos on your accomplishment. Gary Carpe Noctem Sent from the Astro Cave via my Dell XPS Laptop From: C14_EdgeHD@... [mailto:C14_EdgeHD@...] Sent: Thursday, April 14, 2016 3:58 PM To: C14_EdgeHD@... Subject: Re: [C14_EdgeHD] Guide scope (cross post) Hi Gary, Yes, I can run 5-10 minute sub exposures without guiding but a lot more losses than with guiding. I've run hundreds of 5,10 and 15 minute sub exposures and even many Ha filtered 20-30 minute exposures with few losses while using a guide scope. The software is CCDSoft and I find that to be (for me) better than most others. I know that many other folks use an OAG or self guiding imager and I've been there but I find a guide scope to be better. Bob |
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Re: Guide scope (cross post)
Hi Gary, Yes, I can run 5-10 minute sub exposures without guiding but?a lot more losses than with guiding.? I've run hundreds of 5,10 and 15 minute sub exposures and even many?Ha filtered 20-30 minute exposures with few losses while using a guide scope. The software is CCDSoft and I find that to be (for me) better than most others. I know that many other folks use an OAG or self guiding imager and I've been there but I find a guide scope to be better. Bob?? ? |
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Re: New 11" EdgeHD
This is?an update to my original issue/post of a brand new C11 EdgeHD giving unacceptable star trails, with under 5min exposures, using a piggyback guide scope. As is to be expected, Celestron needed to be convinced that it is the scope that is the problem,?and not all the other reasons a piggyback tracking system?can cause a?similar appearing?outcome. Images of?defocussed stars going in and out of alignment as the OTA?went from?zenith?to near horizon?got their attn. but no RMA. They weren't large shifts, just unmistakable. Pointing out dust motes moving about the x/y location on the?image, as the scope moved about,?got no comment, although I thought it was much more convincing than defocused stars, And more measurable too.. Comparing a Meade image to a Celestron image, with the only difference being the OTA's, got nothing. Explaining that I've been imaging for well over a decade, I know what?I'm doing, and talking about, ...?with a web?site full?of evidence to show, got no comment What seemed to work, besides perhaps persistence, was the following Starting 10 arc min past zenith I took consecutive images over 1/2 hr with my guide scope piggybacked?on a high?quality refractor. ?I put the focuser and camera that I use on?the C11, on the refractor. I demonstrated under 5" deviation, RA & Dec, from the ideal track, for the entire 1/2 hr. I then repeated the above, substituting the C11 for the refractor, first?at f10, and then with their focal reducer at f7. It showed the same amount of?image shift at either FL. As a final touch, I tracked for an hour, demonstrating that?the image?shifted along the ?same arc as the OTA took, as it tipped and rotated from nearly vertical, westward along the RA track. That seems to have done it. I'm now waiting for the RMA process to play out.table?star trails,?at well |
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Re: Guide scope (cross post)
Gary Jarrette
Bob I don't know but just about any decent mount with a good polar alignment could take an unguided sub without guiding. So the question is did you turn off your guide scope camera and take a sub of the same duration to see if in fact your guiding was actually doing anything? What I am saying is that a five minute sub is no test. If you get the same results then your guide scope is doing nothing. Take a ten minute sub both guided and un guided to see if you are improving anything. Then go to 15 minutes.? If in fact you notice a difference well then you have proved the guide scope is actually contributing. Carpe Noctem Sent from my space ship via my LG V10 Phone
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Re: Guide scope (cross post)
Absolutely you should be able to use a piggy back?guide scope for 5min exposures. You should be able to do?so at f11 too. The last paragraph on?page 13 of their white paper offers their 80mm refractor and NexGuide Autoguider for just such purpose. They further state?... "For sub-exposures exceeding 10min or so, piggybacked guide telescopes potentially suffer from differential flexure,?for such imaging consider the OAG." I see they are now offering a competitor to Meades star lock system. It better be able to do 10 min subs, or there will be a lot of unhappy buyers, and returns. |
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Guide scope (cross post)
For those?of you who have doubts about guide scopes for imaging I've uploaded some images taken using a C14 at f5.5, a 105mm guide scope and?a SBIG ST8 all mounted on an AP 1200 mount. The FWHM of most of my images averages 1.67-2.11 using 5 minute exposures. They can be seen at??? flickr.com./photos/boshar??? Let me know if you have problems with flickr... Bob |
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Re: New 11" EdgeHD
Interesting, and rough. Not only don't you have the greatest weather there either, but then it gets pricy too. I?found something out today that maybe is not commonly known? or?remembered. I got it touch with Celestron, and?there?are?30dys from date of purchase, where they will pay the shipping on a warrantee issue. I don't know if that policy extends beyond the US, Canada and Mexico? I think Meade used to have a qualified European warrantee center. But that may have been before their warrantee and repair departments went to pieces. There's only been 2 nights where I could do any testing. Fortunately I'd spent the cloudy nights before,?getting ready for the first night. The second night was half way into the 30dy period. But at least I was prepared to, and I did,?some diagnostic imaging. One other interesting thing... I was about ready to dive into and find out if any thing was loose in there. Take out the corrector and check it out.?Thankfully I did not. I would have voided the warrantee. Celestron is apparently VERY particular about the?corrector plate. Not only is it's rotational position?critical, a well known fact for most of us who have taken apart our scopes,?but those little set screws all around the perimeter precisely position the corrector as well. Celestron considers it fundamental to meeting or exceeding?their advertised?claims.?You touch 'em, and you're on your own. Celestron and I are going through the paces that they need to verify if I have a scope that won't stay collimated?when it moves about the sky. It is supposed to. Rigorously. Fortunately I took defocussed star images the second opportunity I had, from nearly horizontal?N & S,?to vertical. So I have those, and?they have asked for them. There's hope for a happy ending Keith From: "alistair.gutcher@... [C14_EdgeHD]" To: C14_EdgeHD@... Sent: Monday, March 28, 2016 3:12 PM Subject: [C14_EdgeHD] Re: New 11" EdgeHD
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Hi Keith,
Sorry I was thinking of the C14 price, the C11 EdgeHD is 4,450 GBP here (6,343 USD), still twice what someone would pay in USA (3399 USD). Yes 20 per cent VAT sales tax here does make it expensive but how come the price is DOUBLE here? I've never understood it. Yeah I use a lot of magnification on double stars, I like looking at Airy Discs at x700 ! Best Regards, Alistair G. |
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Re: New 11" EdgeHD
Hi Keith,
Sorry I was thinking of the C14 price, the C11 EdgeHD is 4,450 GBP here (6,343 USD), still twice what someone would pay in USA (3399 USD). Yes 20 per cent VAT sales tax here does make it expensive but how come the price is DOUBLE here? I've never understood it. Yeah I use a lot of magnification on double stars, I like looking at Airy Discs at x700 ! Best Regards, Alistair G. |
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Re: New 11" EdgeHD
" LRGB image of M1 that has a FWHM value of 2.91 and the LUM sub exposures averaged 1.63" That doesn't make sense. LRGB takes all resolution from the Lum and only uses RGB to colorize that Lum.? So the FWHM of LRGB should be identical to the Lum alone. Anyway, 1.6" is very respectable. Few amateurs ever get below 2.0". Congratulations! Stan |
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Re: New 11" EdgeHD
" is it possible?... to get Sirius and the pup?" Haven't tried and can't really say.? The problem with that goal?is seeing and OTA light scatter. So a very clean OTA under good seeing ought to be able to do it(?)? AO would have no effect?on this venture?because the exp time necessary is a fraction of a second.? But "lucky imaging" (e.g. via?ZWO video) should be able to nail it. Actually, there hasn't been a really significant advance in amateur astro?CCD other than increased sensor size with marginally improved ABG QE. One notable improvement?for some CCD?is less read noise but?that usually?has small consequence for standard long-exp DS (though it can be useful for narrow band).? The old KAF chips?remain competitive and the SBIG ST-10 is still one of the?most sensitive affordable cameras (probably no longer available new).??Unfortunately CCD?has become?extinct in the mass market (Sony announced that they will no longer make CCD) and CCD has been relegated to the expensive scientific market.? Although CMOS has seemed promising for some time now they still perform poorly as hi-res (slow f-ratio) DS cameras due to low-flux instabilities. Stan |
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Re: New 11" EdgeHD
Robert Shartrand
开云体育Hi Keith, I use an Optec F5 reducer made for C14s using a ST8XME so there is almost no corner problems. My mounting rings for the guide scope are attached by a Losmandy D plate at both ends of the refractor just off the carbon fiber tube. It is rock solid. The insulation for the C14 is the same material used to keep the Sun off the dashboard of a vehicle. I put it around the OTA and the dew cap with bungee cords. No rocket science….just common sense. Bob ? ? Sent from for Windows 10 ? |