dieg00

Wow I'm so grateful that you pointed it out, as I would have never realized it by myself. It's definitely impressive, and now you have given me a reason to observe that star using my tabletop newtonian as well!

Thank you for your answer! I will definitely look into that mount

You are definitely right. I'm pixel peeping too much and I'm failing to see the bigger and beautiful picture. I'm intrigued to what you said about Alnitak being split as a double. Which one is Alnitak B? Thank you for your words, definitely what I needed to hear. (And now you have made me happy about getting this lens, so sorry but I'll keep it haha)

I'm gonna buy one then. Do you have any experience with the SVBony one? Or should I go for the COOWOO?

Ok I see. I just tried and at f2.8 or f2.5 I can see no diffraction. May I ask what tracker are you using? And tripod? I'm on the lookout to buy one

Is it fixable? Or something dependant entirely on construction?

I see. Do you use it wide open at f/2? And how long are usually the exposures?

Ahh I see. I think I should try imaging as the lens cools down then. Would a dew heater help? Also, at least with the Taks, is this a defect or something expected based on construction?

Hmm I see. Did you also experience the direction being different on each star? I am asking because if it were retaining clips, wouldn't the direction of the spikes be on the same directions (of the clips)?

My current setup is a Samyang 135mm f2 and Canon 60D. I have been doing untracked astrophotography for a few months, and two days ago I using a iOptron SkyGuider Pro from a friend. After reviewing the lights, I have found an "inverse" diffraction pattern in the brightest stars. Some info: - The diffraction pattern appears to have a different direction on different stars, although the angle between the "antispikes" remains constant (see, for example, the pattern on the different stars of the Orion belt). - I have checked lights from previous imaging sessions, and I cannot find it. However, it should be noted that all previous sessions were untracked, and therefore the exposure time is widely different: 30 seconds vs 1 second. - Similar to the previous point, all my previous sessions were done in a much warmer climate, and this is the first time I am imaging at near 0 celsius. Also, because I had some issues polar aligning it, by the time I took the first photo, the lens had already cooled down significantly. (All the images I took yesterday present the same diffraction pattern on said brightest stars). I would like to know what I can do about this issue, I kindly appreciate any info or test I could do on the lens to try and pinpoint the exact problem and (hopefully) solve it. Also, in case I have to tamper with it, I have seen there is a set of 120 degrees spaced screws next to the aperture ring (which, according to online guides, are useful for fixing the lens in case it doesn't focus on infinity); but there are also 90 degrees spaced screws on top of the focusing ring, what do this do? (I won't immediately use them but I would be interested in knowing about them). Thank you to whoever sheds some light on the issue. PS. I have attached a single light from the session, please let me know if it would be helpful if I share others, or try taking more and uploading them.

So when doing the adjustment I have to rotate it as if I was focusing on something closer to me? (Sorry if the question sounds stupid, I just want to be sure before I do anything). Also, how could I revert the changes if I wanted?

Thanks for the info! When you say the "grip only" what part are you referring to? The cylinder that you rotate to focus? Would doing this process alter the relation between the numbers on the focus rings and the real life situation? As in, would infinity still mean approximately infinity or would the infinity symbol still be the end of the focusing ring so it would mean more than infinity? I hope I make sense haha Also, do I have to do the red halo process on f/4?

What faint stars would you recommend? On my pancake 24mm I would see if I can see the galilean moons through liveview as a check, for example. With the super-takumar it also happens, but it's a 200mm against a 24mm

Hi, I just recently bought a Super-Takumar 200mm f/4 to use with my unmodified Canon 60D and a basic tripod. Using the M42-EOS Neewer adapter, the lens appears to go to infinity focus but doesn't move past it. I'm scared of it not really reaching infinity focus, although appearing to do so. Two days ago I tried to take a photo of M13 (a hard target for a first light, I know), and I obtained the following non-cropped image: Cropping it and adjusting saturation and such I get: Is it infinity focused? I also know I should expect some bloating at larger apertures, and this was done at f/5.6 using the mechanical blades (I have ordered but have yet to receive a few step down rings to prevent diffraction spikes). In total I did 1500 lights (with a exposure of 0.8") at ISO 3200 and DeepSkyStacker stacked 1490 of them. I also did 100 bias, 100 darks and 100 flats (these ones where done pressing the camera against an iPad screen). This was done at a Bortle 6 location on the outskirts of Madrid, so I had to remove the light pollution with Photoshop. I have read the focus can be adjusted but I'm afraid of opening the lens and having the solution be worse than the problem. So, is it on focus? Are there any other tips or things you'd recommend me to do? Thanks in advance! Diego

Thanks for the info!