ฝัง
- เผยแพร่เมื่อ 26 ส.ค. 2024
- In this video: I work on troubleshooting stars that are appearing in my images taken with my EdgeHD 8 that look to have pinched optics, aberrations, and distortions. I performed image analysis, looking at aberration inspector and tilt to determine a baseline of the problem. On the EdgeHD 8 SCT I worked from most simple to more complex steps to check and make corrections, I inspect my EdgeHD 8 for overtightened corrector collimation set screws and dew heater ring. I then inspect my secondary for any abnormalities in its alignment. Then, I had a look at the corrector plate collimation to determine if the secondary was indeed centered into the optics. I found misalignment and show the tools and steps needed in order to make this correction without any expensive collimating tools, all that is needed is a 2mm allen key and a #1 phillips screwdriver.
In the end I found an improvement in my image aberrations, tilt, focus, and guiding! I still have more work to do with tilt and will be covering that in a future video. If you are experiencing distortions of your stars in your astro photos, I recommend having a look at the things i'm covering in this video. For me, I couldn't be more pleased with the results!!
Cheers!
Doug
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#collimation #tilt #aberration #edgehd #sct
![[TH] 2024 PMSL SEA W2D5 | Fall | พลาดวันนี้ จะต้องเสียใจ](http://i.ytimg.com/vi/A5-Cuo12p6A/mqdefault.jpg)
Just a few days ago I had to loosen the screws on my dew heater ring and it fixed my problem I had since I have owned my HD8.
@@legacysearches4481 Hi! Thanks for stopping by and your comment! That’s great that you got the problem fixed! At least I know I’m not crazy thinking that could’ve been it for mine!
Cheers!
Doug
I'I agree with some other comments that the heating from the Celestron dew ring is probably the root cause. If the astigmatism goes away if you turn off the heating then you know for sure it's the dew ring. This is the main reason I stuck with the dew strap for my SCT.
@@physmc1 thanks so much for your comment! I’m looking forward to testing this! Thunderstorms and possible tornado warnings later today so I’m waiting it out for first opportunity.
Cheers!
Doug
Great video, really enjoyed seeing how you step through the process.
@@fotografiabymiguel thank you! This video was kind of hard to keep steps smooth in editing. I hope it came through clearly and described well.
That was very interesting and informative. And the chirping birds in the background added a relaxing touch. Good video!
@@adventuresofshadowdog Thanks Lance!! I appreciate you taking the time to watch and leave a comment!!
Cheers!
Doug
We had this issue with our club’s 14” Edge HD. Problem was the dew heater ring. We stopped using the dew heater ring, went back to a traditional dew heater band around the telescope tube. Problem eliminated.
@@Erniej270 Thank you so much! You are 2nd person calling this out! This just blows my mind, makes perfect sense though! I didn’t even fathom this as cause.
Cheers!
Doug
I have the same issue on my 8“ sct. If the dew heater ring gets more than 50-60% power i have those spikey stars.
@@MarkusSchierz Thanks Mark! Are you using the Celestron controller? I’m considering trying a strap or a shield with integrated heater.
Cheers!
Doug
@@AstroAF yes i do. I got rid of the problems since I don’t set it above 40% power. Sadly that makes it a pretty expensive pwm controller instead of a smart heatercontroller.
@@MarkusSchierz Right, that is what I was wondering because that is not an inexpensive controller. Celestron says not to use any other controller, I’m not sure if that is marketing speaking or not. Perhaps a simple in-line voltage regulator on power side would work. Not sure.
Awesome video, Doug! Great result with the work done.
@@Naztronomy Hey Naz!! Thanks so much! Thanks too for chatting with me before I jumped in to this project!
Cheers!
Doug
Good stuff Doug! I learned quite a bit from this video!
@@DeepSpaceAstro Thank you Rich! Glad you had some takeaways!
Dsa rules ty both for your videos
@@jesuschrist2284 @DeepSpaceAstro 🙇
I noticed some huge flares on my stars this weekend after shooting M15. They only are apparent on bright stars. I was thinking that it was a reflection in the tube or the astrozap dew shield I was using. I'll have to check this as well. The glue/thread lock that Celestron uses in those grub screws is preventing me from adjusting those grub screws at all. I will need to find some kind of solvent that can remove it.
@@mattysastropics I’m going to be testing with no dew heater this week once we have good weather. I’ll be reporting back in a comment.
Thanks for stopping by!
Cheers!
Doug
Hey Doug, speaking from experience with my Edge 9.25 with the 4x corrector adjustment screws along the outside of the scope that you checked for being overtightened. From factory, Celestron seal the holes with thread locker, so if you didn’t remove the thread locker then it’s a certain that the previous owner removed the corrector plate at some point. I had to heat up the Allen Key with a heat gun so as to melt the thread locker when I adjusted my corrector plate.
Also, not certain if you had the dew heater ring turned on at the beginning of your video when showing what you thought was ‘pinched optics’? I’ve seen the dew heater ring cause deformed stars especially if you are using a third-party dew controller.
The start of all my issues was fitting Bob’s Knobs, that was a bad purchase on my part as the knobs are terrible, they come apart if you’re not careful. I eventually went back to original screws and ditched Bobs Knobs resulting in a lot better collimation on my 9.25 Edge. Glad you came right in the end.
@@SimonT65 Hi Simon! Thank you so much for sharing your experience! This is great info. There was no thread sealer in the corrector collimation screw holes. In fact, they were all loose but one.
I haven’t had any issues with my Bob’s knobs but I have the original screws in the BK box.
That is a super interesting thought on the dew heater. I am not using a controller, just on for entire session. The dew heater was on and warm for at least a couple of hours for both of the test images. Next chance I’ll try with no heater and see if I get any different results.
Thanks again! Really appreciate how much value your comments add.
Cheers!
Doug
I have a C8. Since I’m a full time RV traveler and we often winter in Arizona I had my OTA corrector plate and collimation adjusted while near Tucson for a fee. The owner has done thousands of them over his life time. He doesn’t like Bobs Knobs which I have. Says coIimnation doesn’t stay as long as the screws. I picked up one of his SCT focal reducers while there. Interesting you just used a point and shoot camera in video mode pointing to the scope. How far away was the camera? Your guiding is excellent. The HEQ5:mods have transformed that mount. You probably would get better results with a strain wave and your guide exposure would have to be less than on second. Are you getting consistent orthogonal graphs and DEC backlash compensation numbers out of PHD2? If I decide against a strain wave mount maybe a HEQ5 with mods would be better than an iOptron CEM40 or GEM 45 which are $1000 more. Thanks again for helping a fellow SCT owner learn more.
@@KJRitch Hi KJ! I’m guessing the camera was 2-3 meters away. I don’t think it matters too much the distance as long as you can frame it up. I used my camera sensor to tell me if I was level and then used the grid to position center frame. I had to fiddle a lot moving the tripod just right and getting correct height of camera.
Thanks! I’m really pleased with guiding and the results of Rowan/Hypertune! I can’t speak to Strain Wave but I would imagine it would be better in that respect. It is on my list but it isn’t prioritizing as much as other things like HyperStar, filters, etc…
Thanks again! I appreciate you.
Cheers!
Doug
Oh is that what that crap is? I bought a used EdgeHD 8 from a guy on CN that couldn't get it collimated. I collimated the secondary, but in my initial inspection I noticed the index marks on the corrector were not aligned with the casing. I was able to loosen one of the four screws enough to rotate the corrector enough to align the marks. But I suspect the corrector needs to be aligned with center - someone messed with this corrector since it shipped from the factory. I borrowed a Hotech SCT collimator to do that, but I was unsure how to deal with that glue in the holes that is preventing the grub screws from being manipulated at all. I'll try your heat gun trick. Is there any solvent that could be used to remove it all together?
@@mattysastropics Hi Matt, I think you saw his suggestion with heat gun on Allen key. Mine did not have that thread sealer, so obviously had been removed before I acquired the scope.
Cheers!
Doug
Do all the "manufacturers" have almost no quality control?
@@jesuschrist2284 😂 I am convinced that we are Quality Control!!
@@AstroAF hello celestron have $3000 of my earth dollars and sure ill fix it myself :(
@@jesuschrist2284 I feel that!
@@AstroAF sadly i still want to give celestron 3k
@@jesuschrist2284 😂 to Celestron I do give that they have excellent optics and I am very happy with my EdgeHD. I also do love messing around with my gear and taking stuff apart (hopefully putting it back together). It is part of this hobby for me. But don’t get me wrong, I also like stuff that just works and I can start a session and collect photons.
Your telescope must be tested on optical bench. I'm afraid the EdgeHD is not a Classical SCT. And some frustrated owners eventually use it only with the corresponding Hyperstar . This new optical setup EdgeHD is far less tollerant to get pin point stars over the full field . Why Celestron doesnt glue the secondary mirror with this optical solution ? Certainly to be Hyperstar compatible . Anyway some people succed to fix this problem , but they are using some lasers to simulate a bench for a nealy perfect collimation, some choose to buy a flat mirror to collimate with the Ronchi method , because it costs less than sending back their SCT to Celestron. Some are selling their EdgeHD for a Newton musch easier to collimate it. Some are using the classicla SCT and buy the very good Starizona corrector which is expensive but to collimate a classical SCT is much easier. I'm very sad that SCT is a pain to make it good. .Good luck to make it better
@@thierrymartin8378 Hi! Thank you! I think so far I am realizing improvements. I can’t say that I am in Celestron bench spec but from the results so far I think I am in better spec now than I was. Still some work to do. I need to re-check secondary collimation and get in very good focus and then perform a tilt correction next.
Thanks for wishing me luck, I will take any I can get!
Cheers!
Doug