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Cosmic Geoff

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About Cosmic Geoff

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    Bucks, United Kingdom
  1. All rather odd. The Barlow lens in your photo looks exceptionally long. The simplest thing to do might be to buy a 1.25" extension tube. It shouldn't cost much. Less extension will be required if you are focusing on infinity rather than on the far end of your garden. If you were to get the telescope to work without the diagonal, the purpose of the "erecting lens" would become evident. (The diagonal erects the image but leaves it flipped left to right.) The erector goes between the scope and eyepiece. If it contains only one lens, it is probably not a very good erector. Vintage terrestrial telescopes have a two-lens erector, while modern spotting scopes use prisms, making them a lot shorter.
  2. The 'extension tube' you describe is what we know as a Barlow lens, for giving extra magnification. Dismantling the front lens was probably a bad move, for this is unlikely to have been the problem, and there are several ways of reassembling it in the wrong order. (I have had a telescope with the objective the wrong way round, and it did come to focus, but performed poorly). I suggest pointing the telescope at a bright distant light (preferably not the Sun) and trying to establish if you can get a projected image in focus on a card or wall. If you can, then the eyepiece wants to go just behind that position by means of the diagonal piece and whatever extending parts you have to hand.
  3. I ordered an item which was supposed to be in stock. When it didn't arrive, I chased it up to find that it was actually being dispatched from another company who had managed to mislay the order till pursued.
  4. My Maksutov has never needed collimation, ever. Apparently Maksutovs used to be used for gunsights in tanks. If that usage did not put them out of collimation, nothing will.
  5. If that first image is after stacking, it's really not very good. I have had this sort of thing where the raw data was too poor to sharpen up during stacking. My efforts recently to image Jupiter with an 8" SCT and ASI224MC have not gone well either. Bad seeing made the planet have a corrugated limb at times. If conditions are good, you should be able to make out some surface detail, GRS etc in the live image. You should be able to focus on one of Jupiter's moons if seeing conditions are good. If you can't because it is fuzzing around too much, that is not a good sign. -I did not realize this was an old thread!
  6. A 16" Dob? Depends what you want to get out of using it. I know these instruments have their enthusiasts, and are said to give good views of nebulae from dark skies sites. So is this what you intend? The only 16" telescope I clearly remember seeing was a decidedly non-portable 16" SCT installed in an expensive-looking brick observatory. For planetary, it may not give better views than a much smaller instrument, as the performance will be essentially limited by the seeing, and not the size of the instrument. One sees reports from observers saying that they got a better view after stopping down their large scope. Even with an 8" SCT I find that seeing is a major factor, and that I can see a lot more detail via planetary imaging than at the eyepiece. 'Seeing' is also the limiting factor even with planetary imaging using a scope this size. For looking at galaxies, I was surprised to discover that a 4" aperture home-brewed EVAA outfit seemed capable of showing as much from my backyard as my 8" SCT did from a remote dark skies site.
  7. Not my speciality. Any successful shots will show colour if present.
  8. No manual? here you go: http://skywatcher.com/download/manual/tracking-mount/
  9. My 127 mm Mak has never needed collimation, ever. Read the advice above. And bin the laser.
  10. Give it a try. I have found though that budget camera = budget results. Start with the Moon. It is harder to get a target on-chip and in focus than you are probably expecting. Sounds like snake oil. Nebulae usually look monochrome to the eye but colour shows up in a colour photograph. M82 looks lurid in many images but to a visual observer is just a faint grey bar.
  11. I guess that is true if you live in Sweden. It is not so bad from the southern UK but still not great, with Jupiter currently at an altitude of 15 deg or less. An ADC is really essential for planets at an altitude of 15 deg or so. At least one can get one's kit together and practice the techniques while waiting for a better opposition. I expect he's right. My results with a C8 usually seem limited by poor seeing.
  12. Thanks for the camera settings. Evidently the ASI224MC + IR850 filter does have significant sensitivity in the infrared, but less than in the visible region. The Sun emits a lot of energy in the infrared - around 50% of the total output. However I found a spectrum of Jupiter: https://darklondonskies.com/2015/04/15/first-spectra-methane-on-jupiter/ which indicates that the amount of light reflected/emitted from Jupiter in the IR850 band is much lower than at 550nm. So taking these together, there seems ample explanation for my IR exposures being 10x longer.
  13. I am the 3rd owner, and the previous owner said nothing about a warranty. Before dismantling, I noted that so far as I could see there was clearance for the fork assembly to spin on the fixed base, if the latter was placed on a flat surface with the AZ clutch loose. But it wouldn't. I dismantled the assembly following the Nexstarsite pdf. When I got as far as loosening the big nut by a fraction of a turn, I tried the rotation and found that it now moved freely. I continued dismantling and found the specified number of nylon balls, looking clean and lubricated with a light grease. So I reassembled everything, leaving the big nut slack enough so that the base would spin a little way under its own inertia - I tightened it and then backed it off by about 1/6 turn. No evident play. I didn't renew the Loctite, figuring that these parts seemed stiff enough not to undo themselves anytime soon. With the cover on, I connected handset and power, giving it a spin at max speed. It sounds better - will have to see how it performs when imaging.
  14. It's easy to get Stellarium to control the scope once you have communication (which it seems you have). Follow the instructions to set up the scope control 'plug-in' and turn it on for your 127mm Mak. Then a keyboard command will traverse the scope to the object you have selected. I have the NexRemote software but have never tried using it - couldn't see the point while I have a handset. I think the EQ North menu is there because the same handset is used on Celestron EQ mounts. The SLT mount/tripod is too wobbly for any serious astrophotography. For short exposures you don't need the wedge. But feel free to try it, and then I expect you will see why I am advising you not to bother. I used my 127mm Mak for planetary astrophotography, but on an EQ-5 mount, or putting the SLT mount head on a more stable wooden tripod. I tried the SLT mount head on the wood tripod for some deep-space astrophotography (as an alt-az) with short exposures (under 30 secs) and a f5 refractor. It works with no wind and so long as I don't touch anything.
  15. That's the pass band of the ZWO infrared pass filter - it's how they describe it.
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