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Martin Meredith

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About Martin Meredith

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  1. Vlaiv, I think you are over-generalising from one example. I do perfectly well with my 800mm focal length scope and a Lodestar with around 570 x 750 pixels at 2.11"/pix, and have done so for nearly 7 years. Mike JW does great work with his Ultrastar and scopes up to 15". Likewise others with small sensors. It really is remarkable what one can observe with such a setup (see the EEVA observing section for 100s of examples of all types of object). There are various combinations of FL and sensor sizes that would be rated small by today's standards which are nevertheless perfectly adequate for opti
  2. An alternative is to get a small sensor and that way you won't need a coma corrector either. There are actually not that many objects that require a large FOV. The problem with FOV calculators is that they mainly show large objects, which is fine if you plan to stop observing after viewing 20-odd Messiers, but as the threads in the EEVA observing section demonstrate, there is an awful lot of other interesting stuff to observe. cheers Martin
  3. Nephthys -- what a great field, Mike. There seems to be a whole load of faint galaxies to the north too. Lovely round stars too! This asteroid hunting sounds like a fun idea Geoff. I took a look at the data from the MPC, all 650M of it. It would be interesting to incorporate it into the platesolving routine at some point. Martin
  4. That's a really great 'hexagon' SHK group. You don't often see much galactic detail in these groups (at least I don't) but here several of the members show some structure. It definitely looks like you've caught a mag 20.0 galaxy at about 1 oclock and a 19.4 quasar too (looking quite bright). The 15" seems to be performing really well. Envy... Martin
  5. Really interesting to see what these look like with your 15". I imagine they are very rarely observed, as you say. I've tended not to add the more obscurely-named PNs to my observing list but maybe I should. I've tried a few Ms and Ks in the past without a lot of joy. I'll definitely check out J 900 in colour next time I'm out. NeVe 6 doesn't look like a PN. I've seen at least one Arp that looks similar to that fuzzy nest. Platesolving comes into its own for PNs. Browsing through some of my captures over the summer it has been interesting to see where some of them actually are (or missed
  6. Very good to see this planetary in colour. The electric blue is spectacular as is the slightly pink 'eyebrow' at the right in your shot. I often use log for bright PN and have even been known to use linear! Martin
  7. Great haul of PNs. NGC 2392 is really special as is the Medusa, hanging there in space like a ghostly crescent. I thought I'd visited NGC 2392 in colour but apparently not (blue with a touch of pink?). Here's a shot showing far less resolution than yours.This is a single sub, possibly too long at 30s; stacking didn't really help (produced a smoother result, but not what is needed here). Its impressive how you can get great results with a 15" scope and relatively small sensor (by today's standards). What system are you using for tracking? Martin
  8. Thanks for the write-up. There are some fascinating examples in there. I particularly like 529, 801 and 1386 for their strangeness. In the case of VV 529 it would be interesting to know if those satellites are indeed galaxies or just very large structures in the main galaxy. Looking on Aladin it seems that one of them is a galaxy (chance line up?) while the other looks stellar to me. The VV catalogue throws up a lot of surprises. I checked if I'd observed any of these, finding that I have 5 recent observations of VVs in Leo, but no overlaps. Then I saw that there are 125 VVs in Leo alone,
  9. Definitely a tough one, like many of the larger Abells. I'll have a go in colour but if it is hard to see in mono I doubt I'll be able to make much of an impression, but I ought to try with an OIII filter. This one needs a 48" and old-fashioned film photography, obviously... Martin
  10. These are amazingly clean shots given the presence of the full moon -- a real testament to the way EEVA extends the viewing 'season' each month. I recall when I visited this group looking for 3 or 4 quasars in the vicinity in the mag 19-20 class. There are also some mag 18-19 galaxies with apparent distances in the 2.2-2.7 billion light year range strung out between NGC 3718 and NGC 3729. Lots going on in this field in spite of it all fitting into less than half a degree field of view. Small sensors at moderate focal lengths are great! Martin
  11. Thanks Owen. I was looking for such an equation a few years back and never found it... Martin
  12. Pretty good for 2s in colour! Glad to see you've got your EQ platform and dob working. Martin
  13. Intriguing images. Looking at the Aladin SDSS9 layer I'd agree you've picked up these galaxies. Theoretically, a 15" scope at F3.5 with a sensitive sensor ought to get below mag 20. I'm impressed that this is possible in so 'clean' a way in a mere 1m40s made up of 10s exposures. I can't see magnitudes for these galaxies on Aladin apart from GAIA estimates. What's notable about the GAIA data is that the G magnitude (corresponding not to green but to the broad spectral band: see https://www.cosmos.esa.int/web/gaia/edr3-passbands) are similar to the range you label, but red magnitudes
  14. Just to add, your NGC 4015 is Arp 138. Quite a field!
  15. I came across these when looking for VV 1487 (which I believe is NGC 3997), not realising this is also WBL 368 (ignore the placement of the WBL 368 label/circle -- still under development!). It really is a lovely field. My shot was not really framed to maximise the galaxy field, though I notice that I caught NGC 4018 -- yet another lovely edge-on.
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