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Losmandy DSC strange results
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Ray Porter
Greetings all,
I finally got a clear night last night to take the G-11 I'm considering buying outside for the first time. The dew was terrible (couldn't even keep my glasses clear) but I was able to try out the DSC (Losmandy according to the labels). I polar aligned using just the polar bore scope then selected 1-star alignment. I used Vega which by this time was just west of the meridian so I selected it from the 2nd-star list. I centered Vega in my reticle then pressed enter. I then tried to target M13. When the DSC display read zero, instead of M13 I was pointing somewhere about halfway between Hercules and Ursa Major. I repeated the process using the 2-star alignment and estimating the +90 degree position and got almost the same results. Where did I go wrong? I had set the date (which I believe affects on planet location). The mount was leveled and it was certainly well enough polar aligned for visual observing. I had not reset the encoder resolution from the default 4000. The manual mentions 4000 as the default and gives the valid range but doesn't recommend a correct value. Thanks, **** Ray Porter lrporter@... dragon@... ray_porter@... Home Page: "Meddle not in the affairs of dragons for thou art crunchy and taste good with ketchup" |
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Ray:
Seems you had the same seeing in Chapel Hill as I did in Rocky Mount. :-) You are correct in polar aligning, then using the one-star alignment. You are also correct in pressing same button again to "sight second star" when your star on the western side of the mount. You should, however, change your encoder setting to 4096. This is only my opinion, but my Losmandy DSC's on my G-11 use 2048 step encoders with a 2:1 gear ratio, which use the 4096 setting. I have a permanent pier/observatory, so my polar alignment is naturally very tight. I've found that using a high-power EP with a reticle to calibrate the DSC's allow me to center objects that I can't even see visually. Then I replace the EP with a CCD camera, take a 30 second exposure to verify it's there...and bingo! Hope this helps. Regards, Bruce Inscoe |
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Ray Porter
Thanks, Bruce. I'll try changing the encoder resolution to 4096 and give it
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another shot. Let's hope for less humidity sometime soon! **** Ray Porter lrporter@... dragon@... ray_porter@... Home Page: "Meddle not in the affairs of dragons for thou art crunchy and taste good with ketchup" ----- Original Message -----
From: <midniterider@...> To: <Losmandy_users@...> Sent: Sunday, September 10, 2000 6:54 PM Subject: [Losmandy_users] Re: Losmandy DSC strange results
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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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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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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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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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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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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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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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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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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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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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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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I know this problem. You have inadvertently set your scope to
southern RA. It has to do with whether you use a + or - on the second coordinate (on the NGC Max). But I actually had this problem first on a CG5! It was actually outfitted with a southern (manual) setting circle. Some folks on saa helped me figure it out. Some of the things mentioned here are interesting but not as much to the point. If you are using a + when you should use a - and vice versa, you will flip to southern RA and head opposite the direction you intend. -- In Losmandy_users@..., "Ray Porter" <ray_porter@u...> wrote: Greetings all,considering buying outside for the first time. The dew was terrible (couldn'teven keep my glasses clear) but I was able to try out the DSC (Losmandyaccording to the labels). I polar aligned using just the polar bore scope thenselected 1-star alignment. I used Vega which by this time was just west ofthe meridian so I selected it from the 2nd-star list. I centered Vegain my reticle then pressed enter. I then tried to target M13. When theDSC display read zero, instead of M13 I was pointing somewhere abouthalfway between Hercules and Ursa Major. I repeated the process using the2-star alignment and estimating the +90 degree position and got almost thesame results. Where did I go wrong? I had set the date (which I believeaffects on planet location). The mount was leveled and it was certainlywell enough polar aligned for visual observing. I had not reset the encoderresolution from the default 4000. The manual mentions 4000 as the default andgives the valid range but doesn't recommend a correct value. |
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