ippiu

i always take flats of 0,5 sec or 1 sec at gain 150 -200. Peak Histogram at 45-50%: single rgb peaks range from 20% through 80%. They are perfect. (read the sharpcap manual) I also did some tests of differente exposures ranging from 0,1 to 4 seconds: i didn't see any substantial differences...

And if you slew 90° the opposite way, your PA should be almost for sure different. I have a difference roughly of about 2' when rotating from 90 ° east to 90° west. What are you doing to mitigate this little error? It's cone error, i think. Now i'm using IPolar: it is mounted inside the RA axis mount and it should give more uniform reading while rotating the mount from east to west....

Today I returned to seller my RC51 and asked complete refund. Probably returned also cem25EC: as present in RC51, problems also on this mount, after days of test: https://www.cloudynights.com/topic/660863-cem25-ec-03-arcsec-rms/ So i'm frustrating that i'm thinking to sell everything and probably go back to peace: visually with Cpc925.....maybe...

https://www.teleskop-express.de/shop/product_info.php/info/p11067_TS-Optics-61EDPH---5-Element-Flatfield-Apo-61-mm-Aperture-F-4-5.html https://www.teleskop-express.de/shop/product_info.php/info/p9249_TS-Optics-Photoline-72-mm-f-5-5-FPL53-Apo---2--R-P-Focuser.html https://www.teleskop-express.de/shop/product_info.php/info/p7085_TS-Optics-TSQ-71ED---71-mm-f-4-9-Quadruplet-Flatfield-Refractor-with-FPL53-Triplet-Objective.html

Great scope. I exchanged it for Cem25 EC... This is it (still unsold): https://www.astrottica.it/demo-e-usato/3081-rifrattore-apocromatico-sharpstar-86sq-f-54-quadrupletto-fcd-100.html All images taken with Asi294 and 86SQ: https://drive.google.com/open?id=1p0zs2_G61OvRNCaSt1kuY-qU2AWiWd7G

@symmetal Thanks really so much...Now i know that my Rc51 model is not perfect, but acceptable, passable. You say "Many people would be happy with it": I'm not because i bought this scope with just in mind to take large portion of the sky and so i didn't plan to crop the final image. "Have you seen any images from the alternative scope you're looking at to see if it might give better results": Not yet. But few months ago i owned Sharpstar 86Q quadruplet and Ts 100Q quadruplet: they didn't show any sort of issues as those one present in RC51. In the next few days i'll have to decide...

I look forward to seeing here the results about my new images analyzed by your CCD Inspector. And i thank you so much in advance. I have time until next monday to return it to seller and ask for a complete refund. So according to your CCD Inspector analysis i decide if to keep it or to return. I don't want to risk in an another worse replaced RC51 model... If i decide to return it, I would try this: https://www.teleskop-express.de/shop/product_info.php/info/p11067_TS-Optics-61EDPH---5-Element-Flatfield-Apo-61-mm-Aperture-F-4-5.html

@symmetal Thanks, thanks, thanks so much. Analyzing all my pictures (i have many in .png, but i chose 2 images to upload) at 200% on pc screen i had the same your impression: the right side is the worst expecially the corners. But i'm not completely satisfied with my Rc51 because i'm using only a relatively small 4/3 sensor (Asi294): even if the coma effect is very little, it shouldn't be there. Because William Optic says "the sharpest lens ever made for full frame": false How big would coma be on full frame sensor?? I have uploaded several more images. Could you please analyze any of them? I haven't ccd inspector. https://drive.google.com/drive/folders/1NnDBIFAQQLa08hZo3fcv9auwLiD48pRz So i could decide if keep RC51 or return it to seller... I'm so grateful to you @symmetal

Hi to everybody. I have the beatiful gem RC51. And i'd like to investigate if it has the coma issues present in some previous models. I took flat frame. I took a couple of quick images last week before the weather broke forever in .png (i forgot to change the file extension in .fit in Sharpcap). i'm asking everyone a favor: could anybody take a look at my files and say if my RC51 is good? I would really appreciate if someone, more expert than me, could have a look at my pictures. As soon as the weather will be fine (i hope soon...) i will have another test session taking .fit images... https://drive.google.com/open?id=1NnDBIFAQQLa08hZo3fcv9auwLiD48pRz Thanks so much

I look forward to receiving the little red baby...I ordered one from italian reseller.... I had a big and great expactations on it, so reading this topic made me angry and sad... Hope this bad story is caused by just one isolated single badly assembled piece...and not by a common problem affecting all redcat family... Follow with anxiety this topic