MarkS

Hi Antonio, Very nice image of a tough target! Mark

Hi Daniel, I have had no trouble using MLPT for up to 20min subs with only the 3 star config from the PA routine. Regards, Mark

I missed the opportunity to get more data on IC4721 etc. so that will have to wait a year. Still working up the f/6.8 config on the ASA10, I targetted the three closely grouped galaxies of the Grus Quartet - NGC7590, 7582, and 7599. These are quite faint, with surface brightnesses of about 12 mag. The brightest star in the field of this image is 12.8 mag. FOV is 24 X 18 arcmin. Total exposure 3hr 20min: 16 x 5min binX1 L; 8 X 5min each binX2 RGB. I'm sure these faint objects need more time, so I hope to double or treble this as the weather allows. Seeing was ~2arcsec, SQL reading 21.55 (a record for this site) Mark PS: The high res original reveals at least another dozen or so tiny distant galaxies.

Hi Ron, Very nice image! Thanks for posting. Mark

Hi George, I enjoyed looking at the pictorial history of the build. Thanks for the link. Your balance solution is neat - much nicer than my approach of gaffer taping Aus 50c pieces to the right place on the OTA as a final balance tune... Regards, Mark

Hi Ron, The comparison is interesting! I have played with this technique, but not on really good candidates - It's good to see an example that works well. Regards, Mark

Hi Pavel, The last few months have been a bit frustrating here also. You can always go back to the object again and get the colour! Regards, Mark

Antonio, what an interesting one! Thanks for showing it to us. Mark

Tim and Antonio, Thanks for the comments Regards, Mark

Hi Tim, That DE current of ~4A looks very high to me - but I don't have experience with the DDM85 Regards, Mark

Hi all, Just to close the loop on this one - I am now routinely using dithering in Sequence and I am assured by Philipp that it is random. This appears to be so from my experience so far. Mark

Shot this the other night with my Officina Hiper APO 130 running at f/3.9. FOV 2 degrees by 1.5 degrees. (My ASA10 awaits new focuser electronics.) I had trouble with dew formation, so the image, whilst a total of 5 hours exposure, is missing a lot of blue time: R 90min, G 85min, G 30min. Thie reduction in file size causes a loss of resolution of the dense star field, but a A2 print I made looks very nice.

Splendid shot, Antonio! Regards, Mark

Hi Ron, Thanks for showing us this - quite a challenge! I wonder how many unnamed faint nebulae there are out there! Regards, Mark

Thanks Antonio. The final on this must wait a while - my focuser hardware has failed....... Mark

Hi Ron, Beautiful image - and congrats! Regards, Mark

Hi Antonio, Very Nice! Mark

Great image, George! Regards, Mark

Antonio, Remarkable image. Makes my little galaxies look like lighthouses! Thanks for showing us this. Regards, Mark

George, I agree! Mark

I captured these faint galaxies on my first clear night for months. I was testing a new spacer for the f/6.8 configuration on the ASA10N, and there was not much on offer for this set-up. So I targetted IC 4721 without knowing much about it In the event, it was very windy, and the wind increased through the session - so much that the L subs were spoiled somewhat. (The motor currents varied sharply from 0.6A to 1.8A in the gusts) This image is thus a work in progress - it is only 2hr RGB binned X2 - which still gives a reasonable plate scale of 1.3"/px. It awaits a good set of Ls. The integrated magnitudes of these galaxies are 12 -13th. Th brightest stars in the image are around 11 mag. The faint galaxies turned out to be interesting. The largest - IC4721 - is a barred spiral about 90Mly distant, as is the second largest - IC4720. The small jet-like addition to IC 4721 is in fact an elongated elliptical galaxy a further 180Mly distant. ASA10N at f/6.8; DDM60; STT8300M; Astrodon LRGB filters; 8 X 5min subs each colour; FOV of cropped image ~ 24' X 21'. Seeing poor; SQL 20.8; processed in Pixinsight; finished in PS.

Also, don't forget that the balance is affected by the focus position - so only adjust balance when the camera is in focus! Mark

Hi Ian, I'll have a close look at it next time I do a balance. In the meantime, I do use 50c pieces for the final DE balance. It DOES help to get it as good as possible, and doing this beats messing with the OTA in its rings! I've seen wind gusts shifting the current between 0.5A and 1.7A but that is only transient, of course. The real problems occur when the current slowly rises while tracking - until the dreaded PE occurs... Regards, Mark

Hi John, Does this work when you are using Sequence? Mark

Hi Ian, In my experience, it is the settling position of the red line that counts. The yellow bar can move around quite a bit, but if I let the system run for several cycles it settles somewhat. (If you're not on a very stable base,though, it can kick around a lot.) Frankly, I've never worried about it. For me the critical issue for balance is whether or not the motor currents stay below about 1.4A (DDM60) when tracking over a long period. If they don't, a Position Error is on the cards. Because my set-up is mobile, and I must therefore rebalance every session, I only attempt to get balance good enough to stay within that current guide of I have never found tracking performance to be compromised by this approach. I monitor the current with a digital ammeter in the power supply lead to the mount, and, whilst it may not be essential, I recommend it for keeping track of the current draw, rather than looking at the log after a disaster has occurred! Regards, Mark