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Andyb90

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About Andyb90

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    Staffordshire
  1. I hadn't noticed until now but the star profile in PHD2 shows the measured star size in arc seconds. I just checked a screenshot from my last session and it shows 10 arc seconds for the auto selected star, which is well above my guider image scale. The Cloudy Nights post assumes much smaller guide star sizes.
  2. I usually get around 0.5" rms. This was my thinking too. I found the below thread on the Cloudy Nights forum. But within the thread there is this post where under sampling comes up. https://www.cloudynights.com/topic/617386-imaging-vs-guiding-image-scale/?p=8567366
  3. Hi Everyone, I've been reading up on imaging and guiding image scale and I'm wondering if my guiding image scale may be too small. WIth my Evoguide 50ED and ASI290mm mini it is 2.47 "/pixel. I've read a couple of posts on forums suggesting the guide scope image scale should ideally be around half the typical seeing. Looking at Meteoblue for my location that would be 1-2". When I plug in the above values in the ccd suitability page below it does say my combination of kit gives significant under sampling. https://astronomy.tools/calculators/ccd_suitability So I'm thinking could this cause issues with guiding? I do check my stars by zooming into subs in SGPro as they come in. There doesn't seem to be any real issue. Just wondering if increasing my guiding image scale could get stars tighter. I'd be grateful for any advice on this and it would be useful to hear of anyone elses experience. Andy.
  4. Another thing you could check for is dew on the 1600 window/cover glass. I remember reading some posts about it a while back. You just need a night with conditions where dew is likely to form.
  5. Thanks for the advice. I've gone for these cables from Teleskop Express. Hopefully they'll be ok. https://www.teleskop-express.de/shop/product_info.php/language/en/info/p7907_AST-optics-WWPEX---Extension-Cable-for-Dew-Heaters---2-m.html Andy.
  6. Thanks will ensure that is ticked as I am pulse guiding with ASCOM.
  7. Hi Everyone, I'm using 3 Astrozap dew heater tapes. I connect them to my mount hub pro compact. The cable for each tape is quite short, so I'd like to extend them. I think the heater tape cables are just single RCA cables terminating in a male adapter. Would something like this be ok to use as an extension cable? https://www.ebay.co.uk/itm/3m-Metre-Single-Phono-EXTENSION-Cable-Lead-RCA-Male-to-Female-Plug-To-Socket/371040323118?epid=1171936198&hash=item5663ba062e:g:jkcAAOSwlaRaAJQT:rk:1:pf:1&frcectupt=true Andy.
  8. I just found an individual guide image frame. It looks like the issue is on stars throughout the frame. This image is the circled stars from the centre of the frame zoomed in. The same 'tail' is visible on the larger star.
  9. I managed to get a screenshot from PHD2 of the guide star. Do you think it still looks like a lens issue from the screenshot? I guess I'll also need to rule out an issue with the ASI290mm mini too.
  10. Hi all, I was using PHD2 last night (v2.6.5dev7) and ran the calibration routine. Each part was completing in 10 steps. I wanted to increase that to 12-15 steps. So I reduced the calibration step size (in the Guiding tab via Brain icon) slightly from 1000 to 900. I then cleared the calibration data and clicked on the target button, but found if I went back into the guiding tab the step size had been changed back to 1000. So I couldn't get calibration with my decreased step size. I'm sure in the past I've manually changed the step size to increase the number of steps. So I'm wondering if I'm doing something wrong. Or is it no longer possible to manually override the step size? Any help on this would be appreciated. Andy.
  11. Ok, thanks for the info. I think I'll stick with calibrating near the equator and try to get closer to due South. I have a few obstructions, but should be able to get a bit closer.
  12. Hi all, I normally calibrate PHD2 near the celestial equator to the South East at an altitude of around 30 degrees. But I usually pick targets at a higher elevation if I can, where there is less light pollution. Would there be any advantage doing the calibration close to the target instead? Andy.
  13. Just to add from what I understand with CMOS cameras very long exposures can result in amp glow becoming unmanageable. So that's another factor to consider if using CMOS for DSOs.
  14. Thanks for the response. The guiding seemed fine, but I think I'll return the scope for a replacement as I don't think I could ever sell it with this issue.
  15. Hi everyone, I was using the Evoguide 50ED last night with my ZWO ASI290 camera for guiding and a new IR cut filter. I'm using PHD2 and noticed the star shapes seemed to have a 'tail'. The stars were affected across the field. It almost looked like coma. I removed the IR cut filter to see if that was causing the problem and the shapes did not change. Has anyone else seen this with an Evoguide 50ED? I'm not sure if coma is even possible with a doublet. Or could there be some other cause? Andy.
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