Joerg Spelda

Dear Han, I am facing problems when solving images from global cluster. My idea was to study the (faint) variable stars there. Thus I am taking frames of 30 seconds and make frame merging (9 x 30 =270s) to avoid saturation. Some months ago I tried with a DSLM camera (Nikon Z50), noticed solving problems and though this might be a problem of using a DSLM. Now I have an astrocamera (ZWO ASI585MC Air) but I am facing the same solving problem. I tried also other objects: open clusters, galaxies, even...

Dear Han, sorry, I meant a DATE tag and not a TIME tag that is present and used instead of the DATE-OBS tag. All the best Jörg

Error decoding Julian day

Dear Achim, seems we have different targets. With your faint stars defocussing is contraproductive, but it avoids saturation in stars, which would be saturated if in perfect focus. I do DSLR/DSLM photometry. Not all variable stars brighter than 13 mag have an AUID, but most GCVS-stars have one. Dear Achim and Han, I have uploaded my R Cam example to the AAVSO. Enclosed the light curve with my measures (the 7 TG values). They fit perfectly, regardless the images were not taken under perfect contitions....

I wonder, with this out of focus image you try to do photometry? Dear Achim, defocussing is a technique used to avoid saturation in bright variable stars. I was advised to do so by members of the BAV (https://www.bav-astro.eu/ ; sorry at present only a German homepage is available). Admittedly defocussing is disadvantageous for faint stars, and I have to admit that I do no defocussing deliberately. But defocussed images work for photometry very well. So, they have their value, even if such series...

Hi Han, Many thanks for the fast update. The longer names are no problem, especially not during the testing phase. Now even the widefield images are completely measured. Some variable stars are not found by the local database, but I do not wonder that the online database contains a few more. Measurements with both databases are in accordance with each other. But what makes me worried about the function are missing measurements of clearly visible stars. In my CrB example https://get.hidrive.com/AWCMzMLP...

Hi Han, I am really impressed by the fast development – faster than I was able to test it. I had to learn that I needed to download the recent version of the V50 database for proper work. A fantastic tool for the simultaneous measurement of short periodic stars (like Delta Scuti or EW). The latest version works even better, shows more variables and comp stars. But it faces some problems with the images I tried to measure. - These images have been taken by a short focal length (85-100mm, field of...

Hi Han, your assumption was right: I used an image that was somewhat out of focus. Download link: https://get.hidrive.com/F6bAuZpF Look at AZ CrB (15 25 02.74 +29 43 35.3) It has the same brighness than other, recognised, nearby stars. Also: XX Ser (15 46 18.26 +20 52 35.1) even brighter than nearby recognised stars XY CrB (15 36 26.18 +37 22 35.7): even brighter than other stars. In this cases (those two above not testet) the star profile function does not work, while it worked in other fainter,...