Taraobservatory

Hello, The other night I was imaging Sh2-240 and I just cant see any detail. Even in 5min subs under bottle 2 skies. Has anyone experienced this before? I use these coordinates (see image) Here is my equipment is QHY260M with Chroma 3nm filters and an Esprit 80ED Here is a screenshot of the image. What's going on here? Is my filter not working? Is it the orientation? In need of some assistance

Any idea ? Merry Christams

Im getting very curious about these Mesu mounts. I dont see much information accept that they are very good. But what software do you use to controll the mount etc? As far as I can see I could easily do 10m subs with this thing without any bloadting of stars. Do you have any complaints ? Clear skies Roger

Thank you Vlaiv, again, thank you for the information. I think these will come in handy for this purpose. The Wavefront guys got in touch with me and told me bascically what you just did. Its not required to be very acurate, just within a resonable range as the the software dont actually measure FWHM but only concerns itself with difraction. Clear skies

Hello Vlaiv, I was hoping to get an answer from you. I learn allot thank you! So in light of this information, what Skywave asks for is you lopcal seeing in FWHM. And I can get a rought idea from that though SQM reading or Meteoblue, right? an SQM reading of 21.78 would come to 1.3 somethig ? Here is a link if anyone is interested. Software looks pretty interesing. Kind regards Clear Skies

Hello, I tried to search this online and didnt find anyting. Im not using FB so how can I get some info on this? How to look and maybe book? Cheers Roger

Hello, Probably a stupid question, but here goes. What is the relationship between FWHM, Bortle, SQM and image scale? I know what they are by themselves, but can we use a number from SQM and an image scale to determine FWHM? Etc etc. The reason for the question is that a collimation software (Skywave) needs you to input FWHM to do a correct calibration, but how can you know FWHM without taking a picture to measure? If the scope is uncollimated, I assume your measurement of FWHM will be wrong. Please correct me if I'm wrong. Clear skies Roger

Hello, Im currently in the process of making my own test jigs for ccd tilt and collimation of telescopes. Im new to this so I have a few questions. The CCD tilt is fairly simple as I dont need allot of distance to do this test. But lets say I want to do a star test (using artificial stars) I would need allot of distance here. My question is this; can I just increase the distance of the filed flattener from the telescope to achieve a closer focal distance ? Kind regards Roger

Hello, This is the Sharpstar SCA260 V2 FLO sent it from the UK yesterday and it arrived here in Norway today. Ill get stuck in soon and send some pictures of some alignment tests ill be doing. Clear skies Roger

Here is what my postman brought me today Cant wait to set it up! Clear skies

Hi Adam, Ill post next time as I didn't save any of my tests and now the clouds are rolling in. Kind regards Roger

Hello, I have some issues with my QHY 268. The back focus seems to not be uniform. I get elongated stars in 3 corners which they are pin sharp in another. This leads me to believe that the sensor not uniform with the optics. I have also tested with another telescope and the same issues occur so its definitely a sensor misalignment in the camera. I understand that I can adjust this at the front if the camera but I wonder if there are some tips on how to do this successfully ? As my attempts to tackle this has so far failed. Is there some kind of software or an easy way to get this done ? Kind regards Roger

Hei, this looks interesting. Stupid question here, but when you say desired SNR? I think I understand this but I better ask for clarification. What is my desired SNR under 21.78Mag sky ? (Pick a random target) I see that 20 has been put there as a preset but isn't that dependant on the target and sky brightness ? And how does on get to that number? Kind regards Roger

Hello, Thanks for the information Need to look into this. Is it normal for people to travel to other countries for this ? Clear skies

Hello, I came across this forum and been wondering how one goes about creating a star party ? What are the rules and conditions that needs be met ? Cheers Roger

Reassuring to say the least. I can honestly not see any noise in your picture. What is your exposure pr sub here? I have never been able to put my gear to proper use yet. The images I have done is no more than max 10subs pr filter at max 300sec for M101 and 180 for the clusters. Not nearly as much time as I actually need. Just waiting to get started again Clear skies

Thank you so much for this! Great help! I will et you know how it goes Clear skies

I also have a QHY 268M which I will use with my Esprit 80 for nebula. That has a very low read noise. What other CMOS cams can you recommend. One without amp glow and and large enough pixels for a 1300mm ? Kind regards Roger

Indeed, I have very dark skies and allot of potential to get some good photos. I noticed that my 60 and 120sec exposure of M13 was perfect for stars at least. I also did a another with M92 where I exposed for 180sec where the stars are sharp but not as tight as M13. This leads me to believe that my guiding could be better its but good for my mount (around RMS 0.4 which is great). Its a Skywatcher EQ8r-Pro with a 40kg load. See examples in these links https://www.astrobin.com/53lqze/B/. https://www.astrobin.com/fbphrz/ The reason for the 40kg load is because I have a dual setup which I have now dismantled in favour of single telescope configuration because it gives me more freedom to experiment with different telescopes without having to unload a 40kg rig every time. And hopefully my guiding will improve too if only slightly. Not sure I gave you full well but it is 31268 from my measure in pixinsight. I believe this also has to be in your calculations ? Thanks for your help! Really appreciate it Kind regards Roger

My goal is to take as short exposures as possible without adding too much noise. I like the stars to be very tight. But I didn't want to miss out on faint details due to noise from my CCD. Here are some parameters if you dont mind. Read noise 10,78 Dark current 0.018 Pixel Size 5,3 QE 57% A 120mm FL 630mm (f5.25) SQM (Sky brightness) 21.78mag (Bortle 1.4) What would this look like ? Kind regards and clear skies Roger

Oh my, How amazing! And thank you for sharing. This is what I am after! The season is over for me here in Norway due to the sky brightness but ill write down my measurements and send you as soon as the skies get dark again. . Is the calculator available for Windows ? im not familiar with any of the programs you mention. Kind regards Roger

Thank you so much for this. This makes sense and I see what you mean when you say a calculator might not work for all these factors Cheers Roger

You seem to know what you are talking about so Ill ask some newbie questions if you dont mind. Lets take my setup for instance. QSI 638 - Esprit 120 (This one was at full well max setting when I did the measurement off the sensor in pixinsight) (f5,3 , pixel 5,3 , QE 57% , read noice 10,78e , full well 31800e) QHY 268 - Esprit 80 (At what setting should I do measuring for instance ? At what Gain and Offset?) SQM reading is 21.70 so Bortle 1,3 Skywatcher EQ8r-Pro mount (stationary) How would you go about finding the best exposure? Cheers Roger

Hello, Been through a couple of sites now and watched a few YouTube videos on this topic as it seems to be quite useful. Looks to me as it can save allot of people some head ache and money. When I am after is a tool that can calculate the optimal exposure for your setup under your particular sky. I know Sharpcap has a sensor analysis tool which is used to calculate the specifics of your camera, but you also need something to calculate your sky background. Then we can go populate the values in http://www.gibastrosoc.org/sections/astrophotography/optimum-exposures-calculator. This calculator does not talk about CMOS cameras which has Gain and offset etc.. So I believe its a bit outdated (only relevant for CCD). Am I wrong is assuming this ? A tool that can do all this for you so you dont need to jump back and forth to different calculators and softwares to determine your exposure would be amazing. So if anyone has any idea, please let me know. The benefits of knowing this could actually save you allot of money. Say you live under Bortle 4 or 5 sky and invest in a have duty mount for better long exposures which is apparently completely useless with a CMOS camera. In fact (if you use LRGB only you MAY not even need to guide as your ideal exposure times can be reduced dramatically with the same result). Any thoughts and help to understand this better would be welcomed Cheers Roger

There are a few galaxies in there but not sure it qualifies as a cluster Clear skies