Adam J

Can anyone tell me what the input voltage for the main board on the AZ GTI is? I recently damaged mine and I now have a replacement, but I dont want to connect it until I have made sure that the voltage regulator on the interface board that sits between the battery and the main board has not also been damaged. Many thanks in advance. Adam

Might be the off axis guider might be pinching. The presence of some fainter notches in the outer ring of the star test suggests some mild pinching (Which could get worse with decreasing temperature) if it was a cold night when you took the original image then I would say that is likely the cause of the issues. Especially so as you mentioned that it got worse as the night progressed. Did you use a dew heater? In terms of NGC 2903 I would not be unhappy with that result at all. You do have to expect a little bloat in comparison to an FPL53 scope. But I would say that is very acceptable. If you are going to design a lens and know that a little lost of Polly stehl is inevitable in either blue or red then the correct place to shove it is into the red channel. Adam

yeah thats totally wrong. See the reply from space oddities. Adam

Would be useful to see a picture of both the image / stars and how you have the scope setup? For the record it's not designed to be used at 220mm for imaging. You can only image with the corrector reducer. Adam

It's the two ifs that are my problem. Way better to have something that fails safe. Let's say it was a 1/1000 chance of an accident over a lifetime of use. That's too much risk for me. Things can get damaged without realising, sure you can spend your life triple checking but that in itself would still be too much stress for me. And if not for that then the image quality is also superior. Adam

In opinion solar film is not safe. Buy a solar wedge for the sake of your eyes. Adam

Duel narrow band filters don't let much if any blue channel through although it changes from sensor to sensor. I would normally use super pixel mode in stacking and then remove the green and red channels. Then process separately and recombine.

A two inch eyepiece dew band will do the job. https://www.firstlightoptics.com/dew-prevention/lynx-astro-15cm-dew-heater-strap-for-125-2-eyepieces.html Adam

Ok for a first shot. What filter are you using?

All depends how big it is, might have prefaired a refined version of the AZ GTI as there is room to improve that design. Adam

Depends on the rest of your setup to be honest. If you have an osc dedicated camera and off axis guider makes lots of sense. In essence there are two red tube rings that attaches to a small plate with a 3/8 inch camera tripod screw. Just get a vixen bar and screw that plate to the bar.

Got to be honest I did notice it when using my 130PDS (F5) with a 25mm eyepeice. So I think it would bother me on an F4 scope.

I would say it depends on how bad you are at punctuation. If on the other hand you mean coma corrector then I think its more worth while for imaging than visual. It really depends on how much its bothering you, so only you can really say. Adam

I think ES have a thing about allowing for Bino-viewers and protability. But in terms of imaging this is exactly the "feature" that put me off ES scopes. Adam

Thanks everyone for the kind comments! Adam

Performance was greatly improved for long exposures. You could see a very big difference in the dark's. I dont think that i could show you any data at this point though, all on an older PC. Temperature drop was easily 20 - 25c below ambient once I got a TEC from RS as opposed to the rubbish amazon / ebay chinese ones. Adam

maybe my thread. Adam

You would expect to need a corrector even for a 533 maybe something the size of a 178 / 485 you could get away without but not a 533. However, you would still expect the stars to be eggy on all sides not just one, so you may also have a colimation issue as others suggest. I find the best way to colimate a refractor is with a star test, looking for concentric diffration rings. Adam

Planetary Nebula PN G135.6+1.0 Adam

Today's NASA APOD taken with the 130PDS.

A few days ago I was pleasantly surprised to hear that my image had been selected for today's NASA APOD, 14/02/2022 https://apod.nasa.gov/apod/ap220214.html Its an image that I actually submitted almost two years ago. At the time I had assumed the image would not be selected as another image of the heart nebula had been used only a month or so earlier. Am quite chuffed especially as its the only image I have ever submitted. Below is my original posting of the image on SGL way back in January 2020. Rotated for APOD to show the heart shape better. Adam

Yes, mainly duel band but I have seen people complain about it in deep braudband images taken in low LP too. There may be a solution by moving to 200 gain.

It's not the amp glow that causes the calibration problem.

Huum, its clearly mostly an issue with the red. I really dont know that tilt would cause something like this to be honest. Take another image, rotate the camera and imaging chain and see if you get the same result. Adam

You could try looking at early red frames vs late red frames, the main thing that made me think cooling was that flair on the top left of the red, like tube currents. If you mean that you shot in a cycle of 10 frames per filter and then returned to the first filter then I would do as you say and look at the last group vs the first group. Atmospheric refraction can cause this, but its less likely in a mono camera as the RGB channels are independently registered to each other, its something you would notmally see more often in a OSC camera. Adam