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Following on from Flo's post about the new CGX and CGEM II mounts with the leg heigh adjustment locking levers being put on the inside of the legs, I had a look at my old CGEM mount and found that by undoing the four grub screws that hold the leg adjustment collar with the locking levers, I could rotate them so that the locking levers are on the inside as with the new mounts. This will save the skirting boards from being marked in the room where I store my mount and avoid any possible 'trip hazard' when observing. Not sure why this one has come out on its side?!? It was saved in portrait format.

Hello Astronomers, I have some sad news, sad for me anyway, but unfortunately during the final night of imaging my last DSO, the Fighting Dragons in Ara, my CGEM blew up. At about 4 am, I went outside to check on the imaging progress and decided to dim the laptop screen but accidentally hit the "sleep" button instead of the "DIM" button. Usually this shouldn't be a problem.... but when I "woke" the computer up, the CGEM stopped tracking. Not thinking like it's a big deal, I tried to re-center the object and guide star and this is when I realized that there is something seriously wrong as the mount was not responding to my computer or hand controller commands. When I power cycled the mount and hit a RA button, the mount moved, it moved at full speed until the OTA and camera almost hit the peir.... the only way to stop it was to cut power to the mount. Power cycling it a few times did not change anything except that the mount stopped responding in RA completely.... note that the DEC function works as normal. The hand controller is working normally and not reporting any NO RESPONSE error messages either. I went on a fault finding mission and tried a different Hand controller with no change than I opened the CGEM and swapped the RA and DEC motors on the main motor control PCB to determine whether I burned out the motor. With the motor connectors swapped the mount moved in the RA axis and worked properly by pressing the DEC buttons but now the mount is not moving in DEC, so I knew that the motor is not burned out, but the Motor Control board is faulty, possibly the RA encoder/controller chip. I tried to re-flash the MC Board firmware, hoping that it's possibly just a corrupted data in the EPROM, but after a successful firmware flash, that did not change the situation. With is information, I need to get a replacement motor control board, and this might take a while to arrive from the USA... so until that moment I will have to return good old observational astronomy using my 14" Dob and imaging will have to wait for the future. I guess I'm lucky in a way that the failure happened toward the end of imaging my last image, in that last hours, instead of in the middle of it, so at least I ended up with an image. My theory why this has happened: I don't think that accidentally sleeping the laptop caused the mount to fail, at least not the act itself... of course, there is a possibility that it's just long term use and eventually everything fails, since I had the mount for 9 years, and it did do a lot of tracking hours... BUT than again it did work flawlessly for all of this time until soon after I started experimenting with PEC, and I had PEC running when this happened. Could it be that PEC in the mount was trying to move the RA axis in one way, and PHD2/GPUSB tried to move the mount in the opposite way, causing some kind of conflict, or short circuit like/excessive current drain event? perhaps not in general use with quick pulse commands, but when I did sleep the laptop, could it be that GPUSB was stuck in nudging the mount in one direction, and than PEC tried to move it in the opposite direction and that state was held for long enough to burn out the encoder or controller IC? Either way, comparing PEC programmed mount on PHD2 guiding accuracy to no PEC accuracy, the results are so close that PEC might not even be worth the hassle, and PEC is more useful for unguided imaging? I think that when I fix my CGEM, I might stick to NON PEC autoguiding since, like I found, PEC is no, or very little, improvement, such a small improvement that the reason can be caused by just the atmosphere becoming slightly more still within the comparison time... accuracy difference of only 0.02-0.05" arc sec RMS. Thanks for reading and of course thoughts, opinions and experiences welcome. Clear skies, MG

Hi All, Now that my observatory is finished, I wanted to do a as accurate polar alignment as I humanly could do for my Astro Imaging and so started a adventure. I ended up getting a decent polar alignment after a few tries using different methods and wanted to share my results for anyone out there who needs help in polar aligning their EQ mount with the simplest instructions I can put to words. I want to start by saying that unfortunately it is time consuming and there is NO SHORT CUT if you want accurate PA. The more time you spend on it the more accurate your scope will be aligned to the pole. The below procedure worked for me in the southern hemisphere, but it should work just as well, except change the celestial equator from north to south for the azimuth adjustment. I got a copy of AlignMaster and with the original file, I was very limited to the stars that I was able to use for the alignment, this was due to my house, the observatory hut. Another problem was that the alignment using AlignMaster never coincided with the alignment when I used the Polar scope and/or Celestrons "All Star Polar Alignment feature" (ASPA), not even close. Usually out by a factor of 6-7 DEGREES when checking using celestron polar alignment feature to measure the polar alignment (procedure described below). I tried to run the procedure a number of times, again with limited star selection and the polar alignment compared to ASPA was still way off. I determined that perhaps there are not enough southern stars in the sterne.txt list so I added more stars, carefully made sure that they were J2000 down to arc second detail, all southern biased, all below 15 degrees DEC, and yes I had more stars to chose from in Alignmaster but the result was the same as before, 6-7 degrees OFF!! At this point I spent 2 nights playing with Alignmaster, not getting any closer to my dreamt off perfect polar alignment so I determined that either I'm using it wrong (honestly I doubt it since it is very straight forward) or, most likely, Alignmaster is not as accurate as I thought... either way, I decided that the next few nights I'll revert to drift alignment. I spent the next three night drift aligning the mount using the below described procedure and at the end of it I allowed the mount to drift on a eastern star and than a northern equator star for 30 minutes and both instances the star was within the illuminated line marking in the eyepiece, no drift, so I dare to say that I'm very close to target. ASPA Procedure: Roughly align the mount on the celestial pole using the polar scope. Turn on the mount and do a 2-star alignment followed by 4 calibration stars, preferably with a illuminated reticule eyepiece. Press ALIGN >> POLAR ALIGNMENT >> Display Align, this will display the true error of which the scope is out to the pole. To reduce the error, do an ASPA routine and then turn the mount off and repeat from step 2. NOTE: Steps 2 and 3 have to be performed to get a accurate reading of the error. When I do a ASPA the error os display as 0 00' 00" in both axis, obviously that not right and only after the star alignment in step 2 can the computer in the mount workout the true error with respect to the set position of the ALT and DEC on the mount. DRIFT ALIGNMENT PROCEDURE: Do a rough polar alignment using either ASPA or a polar scope. Align the illuminated reticule so that a star follows along the left/right line, referred to as the RA line when slewing the scope in RA. Find a star and center it in the eyepiece. Facing east choose a star low in the eastern horizon, 30 degrees is a good latitude since it is low and not too much effected by the atmosphere. Allow the mount to track unguided for the chosen amount of time and adjust Altitude (up/down) to bring the drifted star back to the RA line. At first you can overshoot the adjustment until the star starts to drift in the opposite direction or there is no drift. Facing north use a star as close to the celestial equator as possible. Again allow the mount to track unguided for the chosen amount of time and adjust the Azimuth (Left/right) to follow star direction drift back to the RA line. NOTE: The star will move left/right along the RA line when the Azimuth is adjusted and it will need to be chased using the RA buttons on the hand controller as the star moves off the FOV, but as the azimuth knobs are turned the star will move closer to the RA line. DO NOT TOUCH THE DEC BUTTONS SINCE THAT WILL CHANGE THE DRIFT AMOUNT OF THE STAR AND THE NORTH STAR DRIFT WILL HAVE TO BE PERFORMED AGAIN. Repeat steps 2 and 3 with increasing the tracking/drifting time until satisfied with the drift amount. Drifting time will need to be increased to see the drift direction as the polar alignment gets closer to the SCP. Starting with drift time of 5-10 minutes is enough to show drift since the star will drift faster when the mount alignment is further from the pole Once there is no or little drift in 30 minutes than that is very close to PA, MUCH less than an arc minute and good enough for very long guided exposures with no field rotation. Generally I start with 10 minute drift, adjust and do 20 minute drifts than as a final check do a 30 minute drift alignment a few times until ideally the star doesn't move from the RA line at all. Make sure that the drifting time is the same between adjustments, this will allow you to determine if the drift is getting larger or smaller by the distance that the star drifts. I alternate adjustments between east and north (Altitude and Azimuth) alignment as one axis adjustment can slightly alter the other, especially at the start of the drift procedure. Drift alignment is time consuming, for example, for my permanent setup I spent 3 nights drifting to get PA as perfect as I can, ideally i would like to be adjusting the mount until there is no drift for 60 minutes (the 60 minute drift alignment I will do next 2 nights. I figure that while the moon is out it is the perfect time to get PA perfected, so surely 5 night spent on it will be near zero error). Of course the more time that is spent will result in a more accurate alignment but spending this much time on a portable setup is impracticable, so drift aligning can be shortened to accommodate the imagers needs, even a basic ASPA and a 10 minute drifting session a couple of times over will allow 10-15 minute subs when guided, my plan here was to have subs of over 40 minutes, even a hour if need be. AGAIN, this drift alignment procedure was in the SOUTHERN hemisphere, so some aspects might need to be adjusted for the northern hemisphere, such as you can use Polaris, no such option down-under and your celestial equator star will be in the SOUTH. ALSO, If I was drifting on a western horizon star, than, instead of moving the star back to the RA line in the eyepiece, I would have to move it FURTHER away than re-center the star using the hand controller. This is where keeping the drift amount times the same to determine if your drift is improving or getting worse comes in handy, if your star drifts more after a adjustment than you know that you need to turn the AZ/ALT knob the opposite way, SO using a star in the east is simply less troublesome. I hope this info will be useful to someone who need help with polar alignment. Next project... to program the CGEM with PEC using a CCD and PHD to record a few runs of the mounts error and upload the averaged recorded waveform. Clear skies.

Yesterday I set my system up for a practice run for Fridays eclipse. When I powered up my mount the hand controller was displaying 'Transmit Data...'. No matter what I tried I couldn't get the hand controller back to the start-up alignment procedure. After messing about for a bit the Sun dropped below our garage so I packed up and bought the mount inside and ran HCupdate. I selected the latest firmware version and programmed the hand controller. I then cycled the power on the mount and verified the copy. This came back as a match. I then ran MCupdate and again selected the latest version and programmed the motor control board. Again I cycled the mount power after this completed and ran the verification option. This immediately stopped saying that there was a mismatch in address 0 it was something like 5643 instead of 5551. I ran MCupdate again an got the same result. I then went back to the earliest file on the GEM list and loaded that. I did the verification and that came back clean. I then installed the next newest firmware and ran the verification and that came back with a mismatch in address 70. As a final resort I retried the latest firmware and again got the error in address 0, 5643 instead of 5551! Going to the version information in the utilities menu I get HC: 4.21 and MC: 6.50 6.50. I don't really want to do a factory reset and start all over again but I feel that this is my only option now. Has anyone else had this problem with a firmware upgrade and how did you overcome it? Any help would be most welcome as I don't want to miss the opportunity of filming this eclipse (I have all the necessary filters btw). Edit: I haven't tried the mount out since getting this mismatch at address 0 message so I'm not sure if there is an actual problem with the motor control.

hi all, been a while since i was on here (thanks to renos and moving to new home). Getting excited to start getting into observing and imaging again but prior to that been looking into PEC. Does anyone have detailed steps on how to properly do PEC (especially using PEC Tool) for a CGEM? Also does PEC have to be done before every object you image or is it a once off things that once you upload to the CGEM its permanently sorted? I am reading celestron blogs, documents and experiments people have undertaken that PEC should only be done before you image an object and it would only apply for that imaging session. Thanks in advance

Hi All, I came across the knowledge of NGC1055 galaxy in Cetus by accident while looking at some Hubble images and thought that this Galaxy was possibly a rarely imaged object since I didn't see any images posted of it. Googling this galaxy there are a few amateur images, but still not as many as other galaxies or objects and seems very unpopular. This galaxy was not in my "Star Walk" app so I thought that perhaps its not in the simpler star map programs that people use? or due to the fat that it is quite faint... it is in Cartes Du Ciel and Star Map HD. Enough of my google babble, tech specs time... this was imaged using my NexStar 8SE on the CGEM mount at F10 (2032mm) through my unmodded DSLRs. I initially started imaging the galaxy using my Canon 7D to try to get a higher resolution but realised that the 7D is not only as sensitive as my 40D, modded or unmodded, but a 600 second sub heated up the sensor to 43 degrees as reported by APT. Surely this would generate more noise but I decided to allow the rest of this and next night to image using the 7D. I was curious about the difference between the sub quality between my 40D and 7D so I changed the DSLR used to the stock 40D and the difference was staggering... the 40D only heated up to 21-23 degrees, there was more of the galaxy visible in the 600 second sub but the subs had a noticeable less noise. Each night conditions were very similar, seeing, temperature etc, so I figure that the reason for higher sensitivity was the fact that the 40D has physically bigger pixels and so more photos hit each of the receptors... Total Exposure time was: 57 x 600 sec subs (20 subs through the 7D and 37 subs on the 40D) 23 x 150 sec subs (all 40D) 12 x 60 sec subs (all 40D) The galaxy was mid height in my northern sky and I always started imaging 10-15 degrees east of the meridian until sunrise, so I only really had about 3 hours per night of imaging it before the galaxy was obscured... that includes finding the guide star, calibrating and start the process which took about 30 minutes. It's not anywhere near the hubble image or most of the amateur images but I hope you like it, thanks for looking...

Hi Astronomers... I decided that after modding my 40D, in the last few years taking a few long exposure images successfully with the modded DSLR even up to 45min (30 mins usually) subs at 2000mm with all subs usable unless clouds ruined the exposure. Lately I thought I'd tackle a new challenge, that challenge being PEC training on the CGEM to see if I can improve the tracking quality (RMS in PHD) and in turn tighten the star bloat a bit and improve the detail, particularly imaging at F10. Currently my attempts failed miserably. Initially I learned the hard way that you can not train PE on the CGEM using the GPUSB autoguider port, can't even have the cable plugged it since the CGEM starts to make a tapping noise and the whole alignment gets confused or theres is a conflict between the autoguider and the handcontroller, the mount becomes unusable until it is power cycled. The second attempt was to connect the NexRemote via COM8 (on my laptop) and generate a Virtual COM32 for PHD to connect to the NexRemote. PECTools connected to NexRemote directly, so had all three bits of software talking to each other. I have installed ASCOM version 6 and the Celestron ASCOM drivers. I connected PHD using ASCOM via these drivers. I aligned the scope via nothing but NexRemote on the laptop, the NexRemote read the GPS and aligned successfully. I located a guide star, calibrated PHD and commenced guiding, which it was guiding with no problems. Till this point everything was smooth and as expected but here's where the problem started... I had PECTools connected and seemingly everything was OK, it found the index, which came up with a dialog box warning that the scope will move up to 2 degrees, which it did when I hit "OK", returning the guide star to nearly the same spot, which I thought was quite good for such a small FOV since I was using the IS21au618 CCD as a guide camera with a 1/4" CCD. I resumed guiding in PHD, hit "Train PEC" to start the training procedure and nothing... where the sine curve is, there is meant to be a yellow line showing the start point and a grey line moving as the scope goes through its 479 second worm cycle. I waited for more than 10 minutes than left it for a half hour to see what will happen and nothing. When I hit stop training nothing changed on the graph. Same thing was with batch training, I left it for 90 minutes and still nothing, no files generated nor was there any difference in the software after I stopped training. I decided to do a PEC training procedure using the hand controller (after starting from the beginning, aligning the scope using the hand controller) on the scope, which it seemed to be OK, PHD was guiding and the mount was recording, after 8 odd minutes it stopped. When I initiated playback, it seemed to improve the guiding scale a bit, but not so much as to be worth while.. but a improvement nonetheless. I tried running everything with administrator privileges with no change. I'm under the impression that the CGEM has a 3 cycle worm period before truly being periodic, so the way to get the best result is to average over 6, 9 or 12 cycles and upload the result. Has anyone tried this and had a similar outcome, or does anyone have any advise... the laptop I'm using is a Sony VAIO running Windows Vista Basic... but all of the controls are working so I'm reluctant to think that the OS is incompatible with the software. The second thing I tried was using "PERecorder" which worked OK with the calibration and verification until I hit "Record" to record the PE... all it did was display a error message, a crossed out rectangle was all that was shown where the PE graph was supposed to be generated and the tracking was stopped of course losing the guide star. When checking the hand control Tracking setup, it changed from EQ-South to "Zone-5"... Normally there is no "Zone-5" option, just OFF, EQ-North and EQ-South. Sorry for the novel but currently I'm out of ideas, if anyone has any ideas, help would be appreciated. Mariusz

Hi all here's my odd thought,balance now I balance the sct with the weights facing east and the scope on the left facing west But when I image the moon or Jupiter the position of the weights is over to the west and the tube is on the right facing east , So should I balance the scope with the weighs to the west ,has that's the side they will be on when I do image with a dnk21 camera tracking and PA are very good ,align master, Pat

Hi All, After a 8 month break due to moving I finally had a chance to do some simple Deep Space imaging. This image is of the Tarantula Nebula in the Large Megallenic Cloud (NCG2070). This is imaged using my modded Canon 40D at F10 2032mm using a Nexstar 8SE on a CGEM mount. The image consists of 12 x 5 min subs, 5 x 10 min subs and 10 x 1 min subs, all in RGB through a IR Cut filter. Currently I'm working on using the PEC feature on the CGEM, and after I've spent a few hours before trying to work out how it works... when it got to past midnight, I was ready to call it a night but decided to frame up on the Tarantula and give it a go... I thought it's not to shabby for a quickie, so I'm sharing it. As far as PEC goes, next time I get to do some astro, I should have NexRemote, PECTools and PHD to give me a average PEC training from 10 cycles... hopefully it'll improve the guiding accuracy and hence detail in my 2000mm imaging close up images. Thank for looking, Mariusz

Hello Astronomers, During the week when I was imaging the Helix Nebula, I was exposing it when it was east of the meridian. So as it hit 15 degrees past the meridian and the meridian flip happened, there was no guide star in the OAG FOV so I had the option to pack up and continue imaging another day or try for another object and hope for a guide star. As the sculptor galaxy was close to the location I slewed to it (with favour western horizon selected in the CGEM settings) and to my joy when the sculptor galaxy was framed a 1/3rd of the frame to the edge there was a guide star in the OAG... WOO HOO ... and so a second object imaging continued. After getting 3 nights worth of ISO400 10 minute RGB subs, I found that after processing the image was very amber at best.. almost sepia... and no matter what I done to it it always looked too green or purple at certain parts... just didn't look right. When I eventually got a chance, I was going to image some pure blue subs to add to the image to correct for the amber look, but as luck would happen, forecast was for at least a week of clouds and rain... this week was no better BUT I did see a break in clouds the other day with a 3/4 FULL MOON!!!! I couldn't afford to let this opportunity go to waste so I imaged NGC253 through a Halpha filter to cut out the moon glow... remembering that when imaging through Halpha in the 40D there is a lot of data in red (of course) and about 30% as bright in the blue channel.... I thought that I could use that added to blue as well as add some halpha to red and perhaps reveal some nebulosity. I only managed 8 x 15 minute subs before clouds started coming and 4 out of those were usable... here is the result. Thanks for reading my babble.... MG

Hi All, When I was waiting for the Tarantula to get into imaging position to grab som Ha and OIII subs to add to the posted image, I decided to do some unguided subs of 47Tuc glob... its only 15 x 60sec, 15 x 30sec and 15 x 10sec subs in ISO800 at F10 using a modded Canon 40D. Seeing wasn't the best but surprisingly the stars were round for being unguided. Thanks for looking, Mariusz

Just a quick heads up for all CGEM users... Celestron has released version 6.51 firmware update. So if you have been missing the PEC capability of your mount, this update is meant to fix the PEC problem where the CGEM was not accepting any PEC program, communicating with PECtools (or any PEC software) nor recorded any corrections. Clear Skies.

I decided a couple months ago that i am going to upgrade to an EQ mount. I am currently imaging with an Astrotrac but as much as i like it, i have outgrown it and am wanting to move onto building up a proper imaging rig. My plan is to buy a mount within the next couple of months and use my DSLR and 200mm lens for imaging until next year when i will be adding a scope to it, or i may even buy an autoguider before that. I want the mount to be reasonable, meaning i want it to be decent with enough features and payload capacity that i won't have to upgrade it for at least a couple of years. I have narrowed it down to 3 mounts: The Orion Atlas EQ-G, Skywatcher EQ6 and the Celestron CGEM GOTO. I understand that the Orion and SW are the same mount. Both are just under £1000 which is my budget. The CGEM is about £300 more, but i am willing to stretch to that is it is worth it. So what would you get if you had to make the decision? Are there any major differences between the EQ-G and EQ6 other that looks, and what does the CGEM have thats worth the extra £300 on the price tag (other than good looks). Would be great to hear from someone who has had experience with any of these mounts. Also, if anyone has another mount they would recommend then i'm all ears! Cheers

Hey guys, After months of clouds and rains finally they are parting and clear skies can be seen. Now I am hoping you guys can assist me, i am after a illuminated polar scope for a CGEM mount, so far have only found polar scopes without illumination which doesn't help much (still makes it difficult when aligning). Anyone got any advice or products they can recommend?

Hello Astrophotographers, Now that I have my CGEM on a permanent pier, I figured that I should get much better accuracy in guiding quality, especially at 2032mm (F10) focal length on my 8" SCT. I spent a bit of time getting guiding results that are at the very least acceptable and thought I’d share my experience with anyone who is looking for info on PHD autoguiding. In the pasten setting up for each astro session and using PHD I was generally getting RMS about 2.2-2.6ish and after stacking and processing, the soft effects were able to be negated to a great point, revealing detail and with results that I was quite happy with (on a good night) imaging at 2032mm using a modded Canon 40D. The stars were round and generally I was able to use most (if not ALL) of the subs generated, even when I was exposing through Halpha or SII for 30-40 minutes per sub. That in it self, I thought, was pretty good for the setup that I'm using... or... I'm just easily pleased. I use a OAG for my exposures so guiding on the same FL as imaging. That said I did spend a bit of time playing with PHD settings, as well as the backlash setting on the CGEM, along with autoguide rates to try to get better guide graph. After a spending a bit of time on both polar alignment as well as tweaking the autoguiding parameters in PHD, I was still getting a graph that showed large jumps, see pics… Nowhere near the near flat line that a few imagers were getting. Although the RMS level at 2032mm did improve, now I’m getting numbers of between 0.83-1.3, so it is definitely an improvement but still didn’t look flat. The test exposures I done at those RMS levels using the 40D at ISO100 on a 40 minute exposure showed round stars and the frame exposure looked good. I decided to investigate to try to improve the graph, and when turning off the guide commands the graph showed large bumps generated by star movement caused by the atmosphere, the graph was very similar, although slightly higher RMS, due to the star moving around obviously due to seeing. At this stage I put my larger graph RMS in comparison to other very flat graphs to perhaps me guiding at 2032mm on a 1/4” CCD and others guiding using a much smaller/shorter FL guidescope where such large seeing related star movements are not picked up at a shorter FL, I base this on the fact that when imaging and guiding while using my 80mm/500mmFL frac where I generally got a RMS of 0.3ish. Using the size of the pixels and CCD on the focal length the results are 0.548 arcsecs per pixel so multiplying that by the RMS I get the guiding is 0.45 – 0.71 arc seconds accuracy (?) which if I’m right, sub arc sec accuracy is OK for AP. I used http://www.celestialwonders.com/tools/imageScaleCalc.html for the calculation. NOTE That until I had decent backlash set on the handset I was still getting intermittent saw tooth like spikes in DEC and RA, and the guide star did spontanously jump large distances periodically. The way I adjusted the backlash on both RA and DEC was by centering a star on the laptop screen and at 1X guide speed moving forward, forward, back, forward, back, back, adjust the backlash and repeat until the star responded instantly. Also my autoguide rate is set at 40% for both DEC and RA. My PHD parameters that seem to give the best guiding at 2032mm are below: RA Aggressive: 50 RA Hyster: 10 Max RA Dur: 350 Search Reg Pix: 15 Min motion: 0.15 Calib Step: 500 Time Lapse: 0 Dec Guide Mode: Auto Dec Alg: Resist Switching Dec Slope: 4.5 Max Dec Dur: 350 Star Mass Tolerance: 1.00 Dither Scale: 0.05 Hopefully some of this helps someone. Also if I'm missing something and anyone has advice to improve that graph, please feel free to share. Clear skies.

Well I've had three good, clear night's here and dry days so I was able to leave my mount hibernated to cut down on set-up time (wish I had an Obsy!) I don't have much worthwhile data to show for my efforts but I've done a lot of sorting out. I can now get reasonable results guiding with my OAG at 2800mm which has been a bit of a challenge but I'm happy with where I am. My images were really noisey though - bad enough to be obscuring the target and I wasn't sure if it was because the setpoint cooling was only getting down to -20 C (usually go to -25 C in winter and this is my first summer imaging) or if it was the 900 second exposures. Anyway, I had a lot of fixed pattern noise that neither darks nor AA5's defect mapping could sort out. Some 90 second subs of M52 convinced me that the noise wasn't solely down to the length of the exposures so I was beginning to worry that my camer had developed a fault... SGL to the rescue and another thread pointing to power leads as a possible source of noise. I'd be running the camera and filter wheel from the same power line as part of a loom, but using a seperate cable for the Atik 383L+ seems to have solved the problem. So pleased to have learnt so much, but this is all I have to show for now. Celestron EdgeHD 11 on a DIY hypertuned CGEM DX, using QHY IMG0H and PHD to guide. 3 x 900 sec L exposures binned 2x2, stacked in AstroArt 5 with a quick tweak in PhotoPlus x4 Hopefully next time I post this target it'll be in colour with a lot more data but I'm looking forward to seeing what I can get out of the scope for DS)s even at f/10. Thanks for looking.