alacant

Hi Unless you're directly below one, I think you're going to be pleasantly surprised. The light-up-the-sky lamps of old have been replaced by well designed low energy versions. The moon is likely to form far more of a challenge. Here's a worst case scenario; shot from around 10km north of Alicante a few days before San Juan. Yes, there's contamination, but hey, it's not bad. ... but with modern gradient removal algorithms, a few taps and you're ready to process. If you really are troubled by this, you have access to a very low contamination zone looking south east over the Mediterranean: the beach😉 Cheers and HTH

Hi What problems are you having? Cheers

Yes. https://siril.org/tutorials/synthetic-biases/ HTH

Hi Keep it simple... D5300, so best to lose any type of dark frame. Noise will be better controlled simply by subtracting the offset; Nikon NEF usually set 600 . Don't bother with in-camera bias. We recommend Siril for all calibration and stacking. Cheers and HTH

Hi everyone Given that spacing an unknown ff on a cheap refractor in the dark wasn't frustrating enough, I decided to complicate it still further by adding the latest AliExpress UHC to the mix. So, here we are with a 72ed, an undocumented ff and an -optimistically named- angeleyes uhc filter Apart from obliterating most of the stars, the combination seems to work. The optical struggle is outlined in this thread. Thanks for looking and clear skies.

Hi everyone We began the trial and error last night. Forget the customary 55mm. We got as far as 66mm ff to sensor.. It's tilted -the darn flattener has an undercut- so it's useless with a compression ring. Have been trying unsuccessfully to find the whereabouts of the original collar without the ring. At least the stars seem roundish. Tilt apart, it seems to be an improvement over the three-element, false colour at the extremities has gone and the stars are well controlled. I don't know if I have the patience to do another session of screwing-unscrewing-dropping-fumbling, Anyway, here's what it's like over aps-c. It plate solves to 345mm.

Hi Long shot, I know after so long... Does anyone have the spacings for the 4 element version? Apologies in advance for the noise; duplicates this:

Thanks again Unfortunately, it's the backfocus distance I'm missing. The three element version came with suggested backfocus distances. These depended upon the focal length of the telescope in which they were deployed. I copied those distances here: The new version has nothing; I was handed a box devoid of any hint of instruction. Maybe the best plan is to assume it's the same as the old version and begin with a backfocus of around 65mm, point at Cygnus and hope it doesn't take all night to nail it. Cheers

Thanks Is the 55mm with the supplied 8.5mm collar in place? TIA

Hi everyone I'm hopeless with refractors. Has anyone experience of these? What bf should we use for a 72ed -fl 432mm- and is that with or without the 8.5mm ring pictured? TIA

My boss asked me to look up 'Pacman Nebula' in Burnham. Yeah, it took me a while too...!

Hi everyone Surprising how the star field changes moving toward the mw. Tried to stick to the same processing, but m29 was so awash with background stuff, I lost a lot of the battle. Probably not how to do it but anyway... Change from 200mm to 150mm some time after 01:00. Recommendation: don't do that. I speak from bitter fumbling-in-the-dark experience! Thanks for looking and do share your versions if you've had a go at any of these. m56, gso203 ngc6819, nt150s m29, nt150s

Hi If your images are ok, perhaps best to leave it as it is. If not, maybe post an example, along with the logs with which it is associated. We then stand a much better chance of being able to help. Cheers

Hi If you've ever dismantled a new sw mount, you'll know of the horrors within; performance issues will become less of a mystery. When you've reached the stage where you're still not satisfied with the images... Suggestions to move on from here: - clean, re-grease and replace the cone bearing at the base of DEC taking care to pre-load it with just sufficient torque that the axis spin smoothly. That may just do it. Even better... - dismantle the whole of DEC, clean, inspect, smooth -very fine emery- where necessary and replace the bearings with known performance equivalents. SKF are a little more expensive but more likely to be within specification than those currently in place. - Still no good? Repeat for RA. The dismantling and bearing part number details are covered here. The only gotcha we'd add on newer 6Rs is to place the axis shafts in the freezer for an hour or so before attempting to refit through the new bearings. The worm shafts are not however interference so are easily pushed into -even SKF- 608s at ambient. Cheers and HTH

The 4/3 gives you an extra 20mm or so, so that may just do it. Otherwise you're going to need a threaded Barlow and/or a low profile t- adapter. This may be a good point to go along to your local astro club who armed with a box full of adapters, will get you focussed within a few moments of arriving;) HTH

So you're still ~10mm too far out. If you don't want to use the low profile adapter, you'll have to go to: Camera > t-ring > barlow, leaving out the nosepiece. Your Barlow should have a t-thread, enabling it to be screwed into the t-ring camera side and clamped into the focuser, telescope side: Why not post a shot of your focuser from last night with the camera attached? We can then maybe help further. Cheers and HTH.

Hi - lose the Barlow, t-adapter and nosepiece. - screw this adapter onto the telescope focuser: https://www.opticstar.com/Opticstar-Nikon-style-Low-Profile-T-Ring.html - attach the camera to the exposed bayonet. HTH

That's the cc doing its job. On a focused image you'll not see donuts. On a well collimated Newtonian telescope, the circles would be concentric. But look at the processed images. If they're to your liking, ignore.

Hi Assuming the optics are good, there's something interfering with the light path, but as we don't know the full story as to what has been changed, perhaps the best (only?) way to diagnose is by elimation. But before that struggle begins, I can see some bright areas around the new secondary spider rim. Perhaps screw heads? These coincide well with the new spike. Next, go one at a time removing filter, cc... Then replace the original secondary holder, reverse whatever you did to the primary, remove the tube flock, try a friend's camera, remove 12mm from the protruding focuser barrel, blacken mirror edges, collimate and collimate again... Here's hoping you find something obvious early on in the diagnosis. Cheers and HTH

Hi everyone Storm dodging on Friday: from astro-dark, awful seeing, m5 5 minute downpour from around 01:00, steady seeing, m92 I'm not sure if it was the rain that cleared the air or that m92 is higher. Or a bit of both. Noisy but ok-ish? Thanks for looking. R10 on GSO 203 ~90min

To bestow upon us that rare event: a good night's sleep!

Hi Welcome. Some great locations in and around El Albir, along with hundreds of clear nights😀

Hi How about a 135mm or 200mm lens to complement your 50mm? They'd be fine on the sa. Good ones to look out for are the old Takumars which will fit your M3 with a cheap adapter. If you're any good at online auction, they go for around €50. Cheers and HTH

Hi Try: https://als-app.org/ Cheers and HTH

Hi 10" mirror? We'd recommend 6 off, 1.6mm wire; 3 replacements and a further 3 passive springs using the locking screws as retainers. These guys are good; less than a week to Spain. Not sure where you are but if you're in a rush, ask for local shipping at the checkout. Full list of all sizes, here. Cheers and HTH