Terrierist Posted October 10, 2018 Share Posted October 10, 2018 I used to live stream quite a bit in an old job and had this Iographer iPad holder as part of my kit. I'd read that flats can be tricky to shoot and wonder if you think that the following set up would give good results - as I'd never managed to shoot flats previously. Basically, I've created a white image in Photoshop and then used it as an image on my iPad to take flats with, slotted the iPad into the iOgrapher and placed it as shown. What are the pitfalls, how could I make this better? I have used Astrophotography Tools CCD Flats Aid to take some images. Thanks for any advice. Link to comment Share on other sites More sharing options...
Guest Tuomo Posted October 10, 2018 Share Posted October 10, 2018 Many astrophotographer uses laptop/ipad screen to make flats. To me theres nothing wrong with this. I use Huion A4-sized drawboard. Maybe use white old t-shirt and cover up the scope to make sure sensor is evenly illuminated. Link to comment Share on other sites More sharing options...
ollypenrice Posted October 10, 2018 Share Posted October 10, 2018 I, too, would use this in the dark or put a black shroud over it. You are also likely to need a way of dimming it to the right level as stated above. Olly Link to comment Share on other sites More sharing options...
Terrierist Posted October 10, 2018 Author Share Posted October 10, 2018 6 minutes ago, Tuomo said: Many astrophotographer uses laptop/ipad screen to make flats. To me theres nothing wrong with this. I use Huion A4-sized drawboard. Maybe use white old t-shirt and cover up the scope to make sure sensor is evenly illuminated. Thanks for the reply and advice, I did wonder if I needed something to diffuse the light Link to comment Share on other sites More sharing options...
Guest Tuomo Posted October 10, 2018 Share Posted October 10, 2018 Just now, Terrierist said: Thanks for the reply and advice, I did wonder if I needed something to diffuse the light Sometimes I still use old white T-shirt and point scope to blue sky. It gives surprisingly good results. Make sure you are not pointing near sun as it could give you bad flat. Link to comment Share on other sites More sharing options...
Guest Tuomo Posted October 10, 2018 Share Posted October 10, 2018 BTW, I think your Polemaster USB port should point to the left side of the scope..... "Retreat the thumb screw and insert the electronic polar scope. Align the USB port to the left side, as shown in the photo. This will ensure that the image will be moved by altitude and azimuth adjustment accordingly. Tighten the thumb screw to lock the polar scope in place." Link to comment Share on other sites More sharing options...
Terrierist Posted October 10, 2018 Author Share Posted October 10, 2018 6 minutes ago, Tuomo said: BTW, I think your Polemaster USB port should point to the left side of the scope..... "Retreat the thumb screw and insert the electronic polar scope. Align the USB port to the left side, as shown in the photo. This will ensure that the image will be moved by altitude and azimuth adjustment accordingly. Tighten the thumb screw to lock the polar scope in place." Wow! Hadn’t realised you needed to do that. Will revisit the instructions. Thanks, Tuomo! Link to comment Share on other sites More sharing options...
Zakalwe Posted October 10, 2018 Share Posted October 10, 2018 I use a LED ceiling tile, dimmed down with about 5 sheets of white A4. I just point the scope straight up and pop the tile on top of the dew shield. This ensures even illumination with no stray light intruding to vary the average ADU. it's important to make it dim enough to ensure that the exposure is not too short. LED and CCFL light sources can flicker very fast and this can cause rolling shutter artefacts in the flats. This would lead to incorrect calibration. As long as the flats are over a second or two then you should be right. Link to comment Share on other sites More sharing options...
Terrierist Posted October 10, 2018 Author Share Posted October 10, 2018 1 minute ago, Zakalwe said: I use a LED ceiling tile, dimmed down with about 5 sheets of white A4. it's important to make it dim enough to ensure that the exposure is not too short. LED and CCFL light sources can flicker very fast and this can cause rolling shutter artefacts in the flats. This would lead to incorrect calibration. As long as the flats are over a second or two then you should be right. Thanks, you have helped me there as I didn't understand the length required, I'd read that an ADU 0f around 20000 was all that is required - my flats are around 1/2 a second. Link to comment Share on other sites More sharing options...
Zakalwe Posted October 10, 2018 Share Posted October 10, 2018 20,000 to 25,000 seems to be the norm. I don't think that it matters too much as long as the flats are consistent. Personally I'd dim the light and stretch the sub length a bit. Sequence Generator Pro makes taking flats a cinch. It has a Flats Wizard...you tell it the target ADU and it automatically runs a series of exposures to work out which sub length gives the right value. It then saves this value for future use. Link to comment Share on other sites More sharing options...
souls33k3r Posted October 10, 2018 Share Posted October 10, 2018 Apologies in advance OP. Just a side question, i see you're mounting you 9x50 finderscope and using it as a guidescope with a QHY5L guidecame i presume. How are you connecting it? I also see the silver O ring that comes with the guidecam. Any close-up picture of this setup? Link to comment Share on other sites More sharing options...
Terrierist Posted October 10, 2018 Author Share Posted October 10, 2018 20 minutes ago, souls33k3r said: Apologies in advance OP. Just a side question, i see you're mounting you 9x50 finderscope and using it as a guidescope with a QHY5L guidecame i presume. How are you connecting it? I also see the silver O ring that comes with the guidecam. Any close-up picture of this setup? Hello! Yes, this is correct, to be honest I don't use it as I am struggling getting PHD2 to work well with it. That is probably down to my lack of knowledge with guiding. I live in a very light polluted area so tend to image at 90 seconds maximum, so don't need to use the guide system. When it is connected, I connect from the guide camera to power box on the EQ5, where it says 'Autoguider'. I'll PM you some images later. Kev Link to comment Share on other sites More sharing options...
souls33k3r Posted October 10, 2018 Share Posted October 10, 2018 1 hour ago, Terrierist said: Hello! Yes, this is correct, to be honest I don't use it as I am struggling getting PHD2 to work well with it. That is probably down to my lack of knowledge with guiding. I live in a very light polluted area so tend to image at 90 seconds maximum, so don't need to use the guide system. When it is connected, I connect from the guide camera to power box on the EQ5, where it says 'Autoguider'. I'll PM you some images later. Kev Ah ok, no worries mate, PM me when you can. Was just interested how your camera was connected to the guidescope because i'll be doing the same. The O ring got me interested as well so just trying to steal an idea Cheers matey. As for the guiding, i live in the light polluted area as well but guide up to 5 min without any issues (only because i don't like taking longer subs with a CMOS camera). I'll reply to your PM and can give you a few hints and things as well Link to comment Share on other sites More sharing options...
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