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Re: 6" Refractor on GM8 ?
Paul Sterngold
As the other posters have pointed out, the GM8 is really a tad undersized
for this OTA. It's not just the weight, it's also the long tube, which increases the moment as well as creates a wind sail. I have used my C9.25 on my GM8 mount and it's barely adequate for visual use. Focusing at high power is a challenge. Now you know why S&T found the mount that the CR150 comes on woefully inadequate! Paul Sterngold --- James Grigar <pt19@...> wrote: I have a 6" Skywatcher, I think about purchase a GM8 system. will GM8 __________________________________________________ Do You Yahoo!? Yahoo! Mail - Free email you can access from anywhere! |
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Re: 6" Refractor on GM8 ?
Rockett Crawford
"Jeffrey D. Gortatowsky" wrote:
I use an MN61 6 inch Mak-Newt on a G-11 and I have the same problem with the tube being long. I've found, however, that if I carefully balance the tube in whatever orientation it's going to be used, then the mount tracks just fine. Rockett Crawford ---------------------------------------------------------------------------- Capella's Observatory (CCD Imaging) |
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Re: 6" Refractor on GM8 ?
Jeffrey D. Gortatowsky
I bought an AP130 EDT f/8 on a GM8 that used the G11 dovetail plate. The
mount is barely adequate for that setup. Breezy conditions made it shake pretty good and rap test settling times were in the 5 second range. That's makes focusing a challenge as well. I have the same OTA on an AP400 and it's more stable. However I also have a G11 and it's the cat's meow for the OTA. It's not the weight that's the problem. It's the torque produced by a refractor's length. You'll be MUCH better off (IMHO of course) in the long run with a G11. It's more versatile in that you can mount all manner of scopes on it in the future. Clear skies, Jeff |
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Re: Losmandy DSC strange results
bert katzung
Hi Ray:
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On the encoder resolution question, I e-mailed Scott Losmandy and he said to use 4096 for the Losmandy LSC hardware. Works for me (now that I have done the "90 degree setting" routine). Bert Bert Katzung San Rafael, CA katzung1@... ----- Original Message -----
From: "Ray Porter" <ray_porter@...> To: <Losmandy_users@...> Sent: Monday, 11 September, 2000 5:13 AM Subject: Re: [Losmandy_users] Losmandy DSC strange results to give it a shot next time out. Based on feedback from this group I alsoneed to reset the encoder resolution from the default 4000 to 4096. I can'tfind anything in the documentation or any marks on the encoders that stateswhat the correct value should be but based on everything I've seen here, 4096 |
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Re: 6" Refractor on GM8 ?
Ray Porter
I went through the same decision making process a couple of months ago.
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Scott Losmandy said that the GM8 would handle the 6" refractor without any problem but recommended the G-11 saddle plate for extra stability. My decision was made for me when a fellow club member offered me a used G-11 at an outstanding price. I'm using my CR150 on the G-11 now but with the GM8 tripod for added portability. ================================================ Ray Porter Applications Analyst Programmer Administrative Information Services, UNC-CH Phone: 966-5878 email: ray_porter@... dragon@... Home Page: "Meddle not in the affairs of dragons, for thou art crunchy and taste good with ketchup." ----- Original Message -----
From: "James Grigar" <pt19@...> To: <Losmandy_users@...> Sent: Monday, September 11, 2000 1:01 PM Subject: [Losmandy_users] 6" Refractor on GM8 ?
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Re: Losmandy DSC strange results
bert katzung
Hi Ray:
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The question of torqueing something out of true worried me when I started this alignment business but the pointing with the system "as-is" was so bad that I felt I had to do something. My method was to drill and tap two 1/4-20 holes in the thick part of the DUP dovetail plate under the rear scope ring. (I'm using an A-P 130 EDF OTA in two A-P rings mounted on the Losmandy dovetail. That DUP goes on a side-by-side plate that's mounted on the G-11 head dovetail.) The holes in the DUP plate are about 1/2 inch inside the holes/screws holding the rear ring to the plate. So I have two inner screws pushing the base of the ring up (instead of actual shim stock) and the two outer screws pulling it down. With both sets of screws snugged in firmly, the ring is held very solidly and the amount of offset is small (about a millimeter) but easily adjustable if needed over a range of zero to about 1/8 inch. And the pointing is good. I don't see any signs of problems with twisting, flexure during exposures, etc. I take the scope off the mount regularly even though the mount is on a permanent pier, but I leave the dovetail plate - rings combination alone so there is no need to repeat the setting up process (adjusting the "shim" offset, etc). If I had to disassemble the rings from the plate every time, I guess I would get an assortment of actual shim stock from a hardware supplier and find the thickness that was just right; then drill and cut it to fit around the hold-down screws, and put it in whenever I was setting up. Bert Bert Katzung San Rafael, CA katzung1@... ----- Original Message -----
From: "Ray Porter" <ray_porter@...> To: <Losmandy_users@...> Sent: Monday, 11 September, 2000 5:08 AM Subject: Re: [Losmandy_users] Losmandy DSC strange results using the Losmandy dovetail system to achieve the results the manual describes?that thePolaris is centerable on both sides, put the dec axis vertical and use Skyaltitude knob to center Polaris up-and-down in the eyepiece. Then getthe consideringCommander now gives very good pointing: objects all over the sky arealwaysin the eyepiece at x20 and usually at x40. evenbuying outside for the first time. The dew was terrible (couldn't accordingkeepmy glasses clear) but I was able to try out the DSC (Losmandy tomythe labels). I polar aligned using just the polar bore scope thenselected1-star alignment. I used Vega which by this time was just west of the halfwayreticle then pressed enter. I then tried to target M13. When the DSC same2-starbetween Hercules and Ursa Major. I repeated the process using thealignment and estimating the +90 degree position and got almost the givesresults. Where did I go wrong? I had set the date (which I believeaffectson planet location). The mount was leveled and it was certainly wellenoughpolar aligned for visual observing. I had not reset the encoderresolutionfrom the default 4000. The manual mentions 4000 as the default andthe valid range but doesn't recommend a correct value. |
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Re: 6" Refractor on GM8 ?
Stephen at lthuedk@... is using the same setup to do photography, you
can see his pictures at: <> if the link gets chopped off then you must reassemble it, its one looong link. In any case its one excellent picture..I would email him and ask for his advice regarding the mount and guiding setup. I would suggest you use a Minus-Violet filter to reduce blue star bloating. The 6"f8 ota is not heavy, but it is long...probably you would need a G11 in windy conditions. I have owned both mounts and they are excellent. "James Grigar" <pt19@...> wrote: I have a 6" Skywatcher, I think about purchase a GM8 system. will GM8Herm Astropics |
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Re: 6" Refractor on GM8
Kenneth Webb (USF)
Hi
I think the G11 would be more stable. It can hold up to 60 lbs and will allow you to upgrade to a larger scope in the future without worring too much (just get another dovetail plate along with the needed counter weights for the new scope). Ken James Grigar wrote: -------------------------- eGroups Sponsor -------------------------~-~> GET A NEXTCARD VISA, in 30 seconds! Get rates of 2.9% Intro or 9.9% Ongoing APR* and no annual fee! Apply NOW! ---------------------------------------------------------------------_-> I have a 6" Skywatcher, I think about purchase a GM8 system. will GM8 handle this scope well? the OTA weight 20 lbs. Plan to use CCD camera for Deepsky. How high the tripod with fully extend ? Should I get the G11 instead of GM8? Any Comment welcome . To unsubscribe from this group, send an email to: Losmandy_users-unsubscribe@... |
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Re: Losmandy DSC strange results
Julie and Tom Carrico
I have the Sky Commander with the Losmandy DSC and the manual states
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4000. I did not believe that number and entered 4096. It has worked just great. With a reasonable drift align (no movement for 5 minutes at 220X), I get the image on my CCD with my 4" Tak and ST-7E about 90% of the time. When it is not on the CCD it is close enough that star matching with TheSky is easy and the object is quickly moved to the chip. Tom Carrico Ray Porter wrote:
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Re: Losmandy DSC strange results
Ray Porter
Yep, I see the 4096 on the web site. The copy of the manual I have has
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"4000 nominal" in the same spot. The encoder housing is the nicely anodized aluminum and matches the finish of the rest of the mount exactly. The manual I have was obviously printed from the web site at some time in the past. Maybe this was an over looked left over from the Dob kit manual and it has since been corrected? At any rate, I'll definitely change it to 4096 and give it another try first chance I get. Thanks, ================================================ Ray Porter Applications Analyst Programmer Administrative Information Services, UNC-CH Phone: 966-5878 email: ray_porter@... dragon@... Home Page: "Meddle not in the affairs of dragons, for thou art crunchy and taste good with ketchup." ----- Original Message -----
From: "Donald J. D'Egidio" <djd52@...> To: <Losmandy_users@...> Sent: Monday, September 11, 2000 10:32 AM Subject: Re: [Losmandy_users] Losmandy DSC strange results really the Sky Engineering Sky Commander DSC which is usually installed on Dob's, which as I saidbefore uses the larger housing 4000 encoders. The Losmandy encoders use the smaller housingbecause of the space requirements created by the gearing. Did you notice the nice anodizedencoder housing and metal gears? Go to Losmandy's website here and it does say 4096 (in red).by 4096the current owner. All the labels say Losmandy so I'm going to try the thesetting. If that doesn't work, I'll follow your suggestion and remove housingback plate to see the label you mention. seethat shows the counts perrevolution and also the wiring diagram for the pins. If your using themetal housed encoder, youhave to take off the back plate and bend down the circuit board the ifthe label on the encoder. Ifis says 2048 you need to use 4096 as the setting. Come to think of it, 2"you are using the Losmandyencoder kit it has to be 4096 as there is no 4000 encoder in the smallsize (S1) encoder housing.The 4000 encoder only comes the The larger (S2) housing which is over planin diameter. The 4000encoder is found most often on DOB's were space is not a problem. alsotogive it a shot next time out. Based on feedback from this group I can'tneedto reset the encoder resolution from the default 4000 to 4096. I statesfindanything in the documentation or any marks on the encoders that 4096whatthe correct value should be but based on everything I've seen here, anythingsounds like the correct choice. tolike the Lumincon DSC's? ie warp factor =0 isguide you to M13, when you get to where ever the DSCs suggest M13 iflocated try sighting the cluster in and aligning on it. Then see yournext target is better centered. |
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Re: Losmandy DSC strange results
Donald J. D'Egidio
Ray,
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If it is the Losmandy DSC you will need the 4096. The Losmandy unit is really the Sky Engineering Sky Commander DSC which is usually installed on Dob's, which as I said before uses the larger housing 4000 encoders. The Losmandy encoders use the smaller housing because of the space requirements created by the gearing. Did you notice the nice anodized encoder housing and metal gears? Go to Losmandy's website here and it does say 4096 (in red). Don ----- Original Message -----
From: "Ray Porter" <ray_porter@...> To: <Losmandy_users@...> Sent: Monday, September 11, 2000 9:39 Subject: Re: [Losmandy_users] Losmandy DSC strange results
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Re: Losmandy DSC strange results
Ray Porter
Thanks, Don. I'm buying this mount used and the encoders were installed by
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the current owner. All the labels say Losmandy so I'm going to try the 4096 setting. If that doesn't work, I'll follow your suggestion and remove the back plate to see the label you mention. ================================================ Ray Porter Applications Analyst Programmer Administrative Information Services, UNC-CH Phone: 966-5878 email: ray_porter@... dragon@... Home Page: "Meddle not in the affairs of dragons, for thou art crunchy and taste good with ketchup." ----- Original Message -----
From: "Donald J. D'Egidio" <djd52@...> To: <Losmandy_users@...> Sent: Monday, September 11, 2000 8:58 AM Subject: Re: [Losmandy_users] Losmandy DSC strange results that shows the counts per revolution and also the wiring diagram for the pins. If your using themetal housed encoder, you have to take off the back plate and bend down the circuit board the seethe label on the encoder. If is says 2048 you need to use 4096 as the setting. Come to think of it, ifyou are using the Losmandy encoder kit it has to be 4096 as there is no 4000 encoder in the smallsize (S1) encoder housing. The 4000 encoder only comes the The larger (S2) housing which is over 2"in diameter. The 4000 encoder is found most often on DOB's were space is not a problem.to needgive it a shot next time out. Based on feedback from this group I also findto reset the encoder resolution from the default 4000 to 4096. I can't whatanything in the documentation or any marks on the encoders that states yourthe correct value should be but based on everything I've seen here, 4096 next target is better centered. |
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Re: Losmandy DSC strange results
Donald J. D'Egidio
Ray,
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Every encoder I've seen has had a label on the back of the encoder housing that shows the counts per revolution and also the wiring diagram for the pins. If your using the metal housed encoder, you have to take off the back plate and bend down the circuit board the see the label on the encoder. If is says 2048 you need to use 4096 as the setting. Come to think of it, if you are using the Losmandy encoder kit it has to be 4096 as there is no 4000 encoder in the small size (S1) encoder housing. The 4000 encoder only comes the The larger (S2) housing which is over 2" in diameter. The 4000 encoder is found most often on DOB's were space is not a problem. Don ----- Original Message -----
From: "Ray Porter" <ray_porter@...> To: <Losmandy_users@...> Sent: Monday, September 11, 2000 8:13 Subject: Re: [Losmandy_users] Losmandy DSC strange results
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Re: Losmandy DSC strange results
Ray Porter
Hi Gregory,
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Trying the procedure you recommend had already occurred to me and I plan to give it a shot next time out. Based on feedback from this group I also need to reset the encoder resolution from the default 4000 to 4096. I can't find anything in the documentation or any marks on the encoders that states what the correct value should be but based on everything I've seen here, 4096 sounds like the correct choice. I'll report back here after my next night out with the mount. Thanks to everyone, ================================================ Ray Porter Applications Analyst Programmer Administrative Information Services, UNC-CH Phone: 966-5878 email: ray_porter@... dragon@... Home Page: "Meddle not in the affairs of dragons, for thou art crunchy and taste good with ketchup." ----- Original Message -----
From: "Gregory David Stempel" <fyrframe@...> To: <Losmandy_users@...> Sent: Monday, September 11, 2000 2:01 AM Subject: Re: [Losmandy_users] Losmandy DSC strange results
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Re: Losmandy DSC strange results
Ray Porter
Thanks, Bert. The same procedure is outlined in my manual.
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Now let me ask another question, how do you go about shimming a scope using the Losmandy dovetail system to achieve the results the manual describes? If you somehow insert shims between the G-11 saddle plate the universal plate the scope's rings are attached to, won't the process have to be repeated every time you setup (I don't have the luxury of a permanent installation)? Should you instead shim between the rings and the scope? That would seem to create a potential for damaging your OTA. Thanks, ================================================ Ray Porter Applications Analyst Programmer Administrative Information Services, UNC-CH Phone: 966-5878 email: ray_porter@... dragon@... Home Page: "Meddle not in the affairs of dragons, for thou art crunchy and taste good with ketchup." ----- Original Message -----
From: "bert katzung" <katzung1@...> To: <Losmandy_users@...> Sent: Sunday, September 10, 2000 11:10 PM Subject: Re: [Losmandy_users] Losmandy DSC strange results Turns out that the Losmandy DSCs call for a 4096 step resolution setting, plusthe "90 degree setting" is *quite* important, for my setup anyway. I foundthat the method described in the SkyCommander instruction book unmasked anoffset in my dovetail mounting plates. The procedure they recommended, whichworked for me, was to flip the dec axis horizontal on one side, center Polarisflip to the other side. If Polaris is not very close to center, the mountingthe DEC mechanical setting circle reading. This will be your "90 degreesetting" for aligning the computer. (Not sure why it's not the "89.24 degreesetting" but that's another matter.) I then go on to do a two star setup and my Skyalways in the eyepiece at x20 and usually at x40.to 2-starthe labels). I polar aligned using just the polar bore scope thenselected1-star alignment. I used Vega which by this time was just west of the givesalignment and estimating the +90 degree position and got almost the sameaffects the valid range but doesn't recommend a correct value. |
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Re: Bert-Losmandy DSC strange results
bert katzung
Hi Jay:
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Sorry, getting my axes mixed up: Should have said: I moved the *RA* axis with the scope to the west so that the *dec* shaft & counterweight bar were horizontal (by carpenter's level, the first time) , and did the azimuth adjust to center Polaris left-right in the eyepiece. Then flipped the *RA* axis over so the dec shaft was horizontal and the scope on the east side, and discovered that Polaris was way to the edge of the eyepiece field of view. That's when I did the shimming. Had to repeat the west side-east side flips a couple of times to average out the error, but after I had the shimming optimized, I could center it on the west and it would then be centered on the east side as well without any further adjustments. The final step was to put the RA vertical as eyeballed from the counterweight bar hanging straight down and adjust the altitude. Hope that straightens it out! Sorry about the mix-up. Bert Bert Katzung San Rafael, CA katzung1@... ----- Original Message -----
From: "Jay Stanley" <jstanley@...> To: <Losmandy_users@...> Sent: Sunday, 10 September, 2000 10:00 PM Subject: [Losmandy_users] Re:Bert-Losmandy DSC strange results
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Re: Losmandy DSC strange results
Gregory David Stempel
Ray,
When you centered on vega and hit enter, do the DSCs tell you anything like the Lumincon DSC's? ie warp factor =0 Also, after centering on vega, hitting enter, then asking the DSCs to guide you to M13, when you get to where ever the DSCs suggest M13 is located try sighting the cluster in and aligning on it. Then see if your next target is better centered. Take care, Gregory david Stempel FIREFRAME |
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Re: Losmandy DSC strange results
bert katzung
Hi Ray:
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I had a similar problem with my G-11 with Losmandy DSC hardware and Sky Commander electronics (which also has 4000 as the default resolution). Turns out that the Losmandy DSCs call for a 4096 step resolution setting, plus the "90 degree setting" is *quite* important, for my setup anyway. I found that the method described in the SkyCommander instruction book unmasked an offset in my dovetail mounting plates. The procedure they recommended, which worked for me, was to flip the dec axis horizontal on one side, center Polaris roughly in a medium power eyepiece with the mount's azimuth knobs, then flip to the other side. If Polaris is not very close to center, the mounting plate under the scope needs adjusting (shimming). After adjusting so that Polaris is centerable on both sides, put the dec axis vertical and use the altitude knob to center Polaris up-and-down in the eyepiece. Then get Polaris dead-center right-to-left in the eyepiece and set, mark, or note the DEC mechanical setting circle reading. This will be your "90 degree setting" for aligning the computer. (Not sure why it's not the "89.24 degree setting" but that's another matter.) I then go on to do a two star setup and my Sky Commander now gives very good pointing: objects all over the sky are always in the eyepiece at x20 and usually at x40. Hope this helps... Bert Bert Katzung San Rafael, CA katzung1@... ----- Original Message -----
From: "Ray Porter" <ray_porter@...> To: "Losmandy Users" <Losmandy_users@...> Sent: Sunday, 10 September, 2000 3:41 PM Subject: [Losmandy_users] Losmandy DSC strange results keep my glasses clear) but I was able to try out the DSC (Losmandy according toselected 1-star alignment. I used Vega which by this time was just west of theaffects on planet location). The mount was leveled and it was certainly wellenough polar aligned for visual observing. I had not reset the encoderresolution from the default 4000. The manual mentions 4000 as the default and gives |
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