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About cesco

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  • Interests
    Deep sky, particularly galaxies
  • Location
    Bari - Italy

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  1. After two deluding years using SkyWatcher AZ EQ6 to handle a Meade 7” ED refractor, I got back to my previous mount, the manual Losmandy G11. I had to have maintenance performed by a specialized firm, and also to inspect the RA and Dec worms bearing screws and Oldham joints most accurately by myself. At last, after a good tweak and regreasing I reliably got round star images in my frames, without guiding, up to 60 s exposure. I don’t care with longer exposures since I was forced to choose capture of many short shots, useful to increase the combined image S/N ratio, after my once dark sky site
  2. Sure that's true with AstroTrac, but Losmandy mounts don't need clutches release when moving the scope by hand... this a very comfortable peculiarity of Losmandy mounts. The fact that the reference star actually follows the green circle strictly when putting back the scope to home position tells that hand motion caused no disturbance to the RA axis set. Rather, I would like to understand whether some additional optimization exists to decrease more the residual error in polar alignement, unless it is the minimum inherent error for that mount.... I should ask the rare manual Losmandy G11 us
  3. Hi everybody, I put the QHYCCD Polemaster on my Losmandy G11 mount not equipped without GoTo system and relative quick motors. Since rotations by 30 to 45 degrees take long when moving the scope with 8x speed (the max allowed by the mount), I move the RA axis by hand, gently grasping the counterweight bar and pulling it as smoothly as I can. Moving the scope by hand is strongly not recommended in the instruction manual, as this may disturb the axis setup. In turn, axis disturbance may depend upon RA clutch release, which I can understand... although this is absolutely unnecessary for Los
  4. I'm afraid I can't take advantage of higher ISO for short exposures since my camera, Atik 428EX has no ISO, as well as gain, regulation. I don't even know what its fixed ISO/gain values are to get at least an idea wether they are in the high/medium/low range...I searched in the Atik manual and site to find out those values, without success... Here is one of my first short shot experiments, IC432, 45" shots, 100 R, 100 G, 120 B, under strong moonlight. Meade 7" ED achromatic refractor. Looks terrible! IC342 45 dwnhis1 rgb RGXRGB4 MOPM1 rj.bmp
  5. I see... by reasoning in terms of photons, that's straightforward. So it's better not to try a Hubble palette, right?
  6. Thank you! Very nice stuff...I'm happy to get material to study and experiment. Does your tool also gauge skyglow? This would be very useful for comparing results. Another topic I would like to discuss is the effect of the passband of filters. I use RGB dielectric filters from Baader Planetarium, with 100-nm passband, plus a Neodymium skyglow filter also from Baader. I guess they will affect the background light differently...any problems?
  7. I red a treatise on the subject by Alessio Beltrame: https://www.alessiobeltrame.com/segnale-rumore-e-calibrazione/ (in Italian) and found a strict analogy with the accumulation method I used to improve the SNR of weak EPR spectra I worked with in my professional job. I was naturally attracted to the multi-short-shot method I soon understood to be a powerful weapon against light pollution. In addition, similarly to what we do in planetary imaging, though in a higher time scale, it turns out to be also useful in neutralizing setup defects and winds blows, as well as seeing. In fact, just by low
  8. I am going unguided since last summer, annoyed by the bad performance of an AZ EQ6 with a too heavy Meade 7" ED achromatic refractor. I resorted to unguided imaging also after realizing that my once upon a time dark site has turned to a suburban to rural transition site. I find that statistical cancellation of background light by stacking many short exposures, which increases the SNR by the square root of the image number, is better than subtract background light accumulated in long exposures. To me, it makes no sense to accumulate image photons together background photons, as successive photo
  9. Hi all, Before turning to AZ-EQ6 GT mount, I tried to upgrade my previous Losmandy G11 mount to autoguiding by use of a SBIG Relay Box connecting the PC to the mount through an ST4 cable. I didn't intend to transform it into a goto system -it remained manual- just wanted to realize an autoguided system, and I succeded for short exposures up to two-three minutes, but I wasn't able to scale up, hence I turned to the SkyWatcher. My Losmandy dates back to the end of 1990's, but never showed backlash and worm-gear play like the brand new AZ-EQ6 GT did. I was quite deluded by that, and I still
  10. Thank you. Also my suspicions always were more on length than on weight, even because I also put on an additional black cardboard lightscreen to the original one thus increasing the total lenght by 80 cm more....to prevent dew I shoud turn to an efficient electric resistence....this is another drawback to be addressed. Cesco
  11. Hi, 12 years ago I was forced to turn astrophotographer from visual (close double stars and planets) observer because of steadily and heavily growing light pollution of my observing site. Many years ago the Milky Way was plainly visible after nautical twilight while now it is NO lomger visible at all, and only three to four UMi stars are usually visible through the night . So I first resorted to a larger aperture, but the trick lasted few years, and then I decided that more photons had to be collected thus starting astrophotography. To be said I am not the one willing to load my big ref
  12. Hello everybody, I am going to apply Permanent PEC correction to my AZ-EQ6 GT SkyWatcher mount in an attempt to eliminate most minor negative contributions to my so-and-so autoguide. I will do that by following instructions on the SynScan manual. Does anyone have some advice? I also started using Guide Assistant of PHD2 and applying the calculated min-move and backlash changes suggested by the system. More, I tweaked the worm and gear bugs of the DEC axis to reduce the backlash, and after a few attempts I found the right position between screeching and jerky movements of the mount at
  13. Hello, I’m strongly interested in getting Mel’s (Astro Baby’s) tutorial for disassembling/fixing/reassembling the SkyWatcher AZ-EQ6 mount from Synta. I know it should be somewhere in East Midlands Stargazers website, but it seems to be unreachable. Maybe she also posted something like that in Stargazers Lounge. Could someone give me please some help to find it out or to contact Mel in order to ask her for it directly? I'm also looking for contacts with Scott Cunnington, author of a tutorial on th
  14. It seems that a large washer that also sits there is missing....
  15. I can judge a mount better since when I started autoguiding. My 18-years old Losmandy G11 (manual) proved to be better than my new SkyWatcher AZ EQ6. I still regret buying the latter instead of the upgrade kit from Losmandy to transform the G11 into a GoTo system. Nonetheless, I must admit that after a bothering and long training, now I can manage the SkyWatcher so to push guiding up to 15-min exposures (rare), usually 5-10 minutes.
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