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I am new to astrophotography and to the forum. Have been using a Seestar for the last year while getting my HEQ5 mount, Evostar 120, asiair plus, asi533mc pro, Uniguide 50 guide scope, ZWO 5x 2 inch filter wheel. I lose tracking and don’t get good 300 second subs. I have a smiley face with polar alignment, doing 3 sec guide exposures. I have the mount set at .9. RA around 60 blue line red Line Dec about 70. Seems to do ok for awhile. Anyways have you have any help with the gestalt of the settings help would be appreciated.
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So you're getting a total RMS guide error of 0.9"? That's a bit high but not unheard of. I assume you're using PHD2 for guiding. Have you done a guiding calibration? Usually if you are loosing the guide star it's because the calibration is off. Try starting off a session with pointing the scope close to the meridian and run the PHD2 guiding assistant and accept the values it gives you. Run a calibration and you should be good to go. If you still have the problem after slewing to your target, PHD2 might not be getting pointing information form the mount. This is critical for PHD2 to adjust calibration of different parts of the sky. Also, make sure that once calibrated, you don't rotate the guide camera. If you do you will invalidate the current calibration and it will have to be done again.
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No not my rms error it’s a factor on my mount settings that seem to coincide with rough movement of mount . Hard to explain when I don’t know exactly what I’m doing. Will concentrate on great PA and guiding from start before going to target. Thanks for follow up !
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Hi Tony, Are you tracking with or without autoguiding? (do you use an autoguiding software like PHD2?) If unguided, performance depends on the tracking capabilities of your mount (unlikely that you can reach 300s). If guided, then there could be a lot of reasons for loosing the tracking, from wheather (thin clouds, airplanes passing by), to cable connections, calibration in the guiding software or even more severe: the optical path of your polar scope might be off-axis (it happened to me with my iOptron ZEQ25, the polar scope was not well aligned from factory, which gave me the false impression that the polar alignment was Ok, while it was shifting away in time. Better maybe to share a screenshot with your guiding graph. |
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If I read you correctly, you're using the ASI Air to guide and shoot right?
Hope at least one or two of these things will help a bit! Good luck! |
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Thanks everyone for the great replies. Last night things started out good PA with the smiley face all within 1 sec. Then I started the guiding at Polar alignment and my RMS was running at .7. Started imaging Whirlpool Galaxy with 5 minute subs got to around the 12th. Wanted to change the filter as I had a quad filter in and wanted just lpl filter and switched it on filter wheel thru asiair then the device shuts off. Restarted it so left Quad filter in and went to Bubble nebula and it took 15 subs then lost ability to go with good guidiance the aisiair shut off. I don’t know if this device is busted or not. I have it hooked up to a 500 watt Jackery Battery. Kind of frustrating since the clarity of the images are great IMHO.
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And why not 30s ? I don't do guiding (too long to use, usually i cannot loose 1 hour to have a functionnal guiding) and use "lucky imagung". I don't have any problem with sats, planes, bats, owls and so on.  And you can take nice pictures. Just have a look on my page. I have a 115/800 with ASI553 (MM or MC) on a ioptron HAE43. Yes the mount is expensive, but I had a EQ5+ et was getting crazy with the same problems than yours. I am too old for this sort of <censored>. Now I can take pictures et not trying to do them. Free pub for Ioptron, wich is far from perfection sadly... |
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Eric B.: I agree Eric, this is certainly a viable way of working with most modern CMOS cameras. In fact, that's the way I used to image until just recently. I also think that as CMOS cameras get better, particularly if we ever get the new OCS sensor tech that does away with the Bayer Matrix, QE will go through the roof and very short subs with no guiding will become the norm. |
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Totally agree, Tony !  But unfortunately this does not replace the sky of Atacama! …  |
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….especially for a guy who images in his back yard near downtown Tulsa!
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Wow, Tony you are just 150 miles away from me in Derby, Ks. Currently bench testing scope will download Bubble nebula since I am sitting around. Thinking of getting Am5 or Sky-Watcher 100i with dual saddles and get a redcat 51 to put on one of saddles. You have great images
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Thanks Tony, us mid-westerners gotta stick together! If I'm ever up your way, I'll let you know. |
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The OP is new to tracking and guiding so I will add some thoughts and info that might be helpful. Something almost no one does before charging off into guiding, is to work out the mounts native performance. to do this you need to shoot some unguided subs. see how long you can shoot without star trails becoming evident. it might be 30 seconds, or maybe 60 seconds or if your lucky 180 seconds. its unlikely to be more unless you have a premium mount. what you will discover is that the mounts star tracking performance depends almost entirely on polar alignment. once you realise this you will start chasing better polar alignment. I find 20 to 30 ARC seconds is a great place to be, and 30 arc second to 1 arc minute is an ok place to be. anything between 2 and 5 arc minutes is not good enough, and needs to be improved. even with my little AZ/EQ5 Pro I could shoot 120 second subs at 560mm focal length when PA was just about perfect, but only 30 seconds when it was not. once I could shoot 120 second subs without guiding, I added guiding and this improved things another step. Remember if PA is just about perfect, the DEC axis hardly needs to move at all, and this makes the DEC guiding movements less dramatic. took me a while to figure this out. Clear Skies and good luck. |
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+1 on all of the above.
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I came back to this thread that I started awhile ago and my technique is so vastly different and improved. I have moved from a guide scope to an Askar OAG which has a large prism and I use the asi174 guide camera that has high sensitivity, resolution, and gain (up to 400). It isn’t as good with the 120 around .6. I am getting on a clear night with Great Polar Alignment rms value of .3 to .5. With the guidescope the best I got was .8 to 1.2. So thanks everyone, I am evolving with this hobby. Amazing images on the site.
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Tony Carro:  IC 1805 Watch Peter Zelinka videos on tracking. It is the least discussed, but most important component. ASIair properly adjusted tracks amazingly. Plus, you can ask him questions and get real answers. |
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I had watched his videos Mark and it is very helpful as he also has an Askar V like I do. He talks about the stuff that is important and trying to mirror his techniques.
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I'm relatively new and I'm also functional reconstructive surgeon. I'm more of a plumber. Unlike true plumbing that is very linear I live in abstract and conceptional world. Biology is very forgiving, this is not so much. Collecting great data makes the other steps so much easier. Tracking your guiding star is key. I only do 600 second images. You need to look at astronomy tools. It will give you your tolerances for tracking. Learn your equipment first. Once you are dialed in and have great date, processing is so much easier. Happy New Year. I say would say "clear skies", but I leave that to people that offer free advise at the highest level. mark |
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I have the HEQ5 and its use was in B7 skies with a huge soccer complex an eighth of a mile away. For starters, do not trust the level on the mount head. Be meticulous in leveling the tripod. Dial the PA in to under 20". I would often get near 0" error (depending on the mosquitoes). Exposures were set to 2 seconds when guiding. Pay attention to focus on the guide camera. Use the guiding in the AA+ to determine the size of the guide star and focus to the lowest fluctuating numbers. Start your guide camera gain at 28. ASIair loves to pick dim stars that bounce all over the place due to fluctuations in seeing. Increase your gain by 2, back to guiding (you'll see improvement in the star)… increment gain by 2 more. If you try to increase by 4, the guiding will reset, so don't. Do this until your star is just bumping 255 (full well). You should see great improvement in the guide star. I have often achieved .2x" RMS for extended periods on very clear nights. That all said, the HEQ5 sits in the shop since I have acquired the AM5 and the WD-20 (a real pain in the butt thanks to OnStar). Good luck! |
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Right now I play with the gain and exposure time to adjust brightness for aa+. I am more visual and I adjust till I get a contrasting view. Image from guide scope is sharp using the Askar micro focuser on OAG. Image thru tube is sharp using the OTA with EAF. Guide cam has max gain of 400. Usually around 60 to 80 is where I end up.
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In nights of decent seeing with an EQ6r-pro I'm getting pretty solidly in the mid 0.2" RMS range here in Oklahoma unless the seeing is really bad. You should be able to get similar numbers. I shoot at 900mm and I think guiding to that accuracy should handle FLs up to 2000mm without any issues.
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Tony Carro: What is the acr seconds? Most imaging is .300 to .600 seconds. If you in the of .5 your good. You optics may tolerate 1.5, but less than .5 is the goal. you can use ASIair Studio to look at your images. Your gain seems high, should mimic a real sky that is a bit bright, you really need to go to astronomy tools and know your tolerances, google it and you will learn and be amazed. You can't tell you if your good if you review\ images in Asiair studio. Delete the bad. |
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Currently my setup gives me .3 to .5 rms. Easily does 300 second subs that I rarely toss a frame. I am enjoying the setup before imaging. Don’t understand why my PA changes to average alignment versus after I have gone thru aa+ and get excellent PA.
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Tony Gondola: wow. thats very good. are you high in elevation ? I just bought an EQ6R-Pro to use with my smaller Tak 106N, as I stole the Taks mount (CEM-120) to use with my RC-10. I didn't think anything like 0.2 would be possible with an EQ6R and thought that 0.5 or 0.6 would be considered good. it gets here in a few days which is exciting. |
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I'm only about 400 feet above sea level here. To get that performance took accurate polar alignment and a 25A red filter on the guide scope. My guiding exposure time is 2". I think the latest versions of the mount with belt drive are much improved over older versions. From everything I've looked at, it's clear to me that PHD2 is very sensitive to seeing, otherwise the filter wouldn't make much difference.
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