globular

Yes that's correct. A 16mm eyepiece with 60 degree fov will work just fine. You may even just about get away with something like the APM UFF 18mm (giving your target 40x ?) but it will only fully illuminate 55 degrees of the 65 degree fov, so there will be some vignetting in the outer 10 degrees. Some people report that they don't mind it, while others don't like it. Removing the nosepiece from your WO BV and directly screwing it to a diagonal instead will save you those precious few mm. The Baader BVs (and some others too) have adapter options to achieve this. You'd have to do some (scary) hacking to achieve it with the WO. Or you could try without a diagonal.... might not be practical?

Rob was asking about the Linear / Mirror Binoviewer "as sold by Bresser and under various other brands". The Bresser are marketed as 22mm but: 1) people who own them and have measured them report they are actually around 17mm 2) all the different brandings are actually the same design and most now accept and report them as 17mm (e.g. FLO's own StellaLyra version https://www.firstlightoptics.com/binoviewers/stellalyra-125-linear-erect-image-binoviewer.html ) If you know of one that has been measured closer to 22mm I'd be very interested to know.

The mirror BVs only have around 17mm clear aperture so your 24mm 68 degree eyepiece will vignette down to about 41 degrees.

Sounds familiar. I've started making voice notes while at the eyepiece. The native iphone voice memos app is fine. Or you can pick up digital dictaphones easily enough. I do have to find time the next day to write them up - but they help very much with getting all the key observations from a session. My reports now are so much more detailed than before. And there is nothing to get in the way or slow down my excited flitting around - increasingly important as the number and durations of decent sessions seems to be on the decline.

I got this "sturdy workshop stool" for my observing... Weight limit is 150kg = 23.5 stone or so. I'm (cough) about at that limit and the raise and fall mechanism works very nicely and it's all very stable. It's not available any more where I got it, so I can't provide a link... but maybe you can find something similar?

I think the moon / ocean interaction slows rotation, not increases it. So more ocean leads to more breaking not more acceleration. Ice melting from a few big places and becoming more spread out throughout the oceans might mean the axis of rotation shifts a bit; which can change spin rate slightly. This doesn't feel like the right explanation to me though. Shrug.

I think meteoblue has the same error for tonight for me. 2.5 hours of astro darkness, no moon, no clouds, reasonable seeing, just a bit of jetstream.... 🤔 Clear outside seems to agree too. Even more suspicious. Jetstream gap for my location too. Not great but I'll take it. And all the models seem to agree, making it more likely to actually happen.

+1

Are you saying using binoviewers allow you to see smaller exit pupils more easily than one eyed viewing? I had very floater free vision until a year or so ago - since when I've had to limit my very high magnification / small exit pupil viewing. I miss it very much... maybe a binoviewer would help?

Please report back how you get on... be interesting to hear.

I suggest you make a simple off-axis aperture mask for your 10". You should get something like 4" fully unobstructed. I think you'll find the views will be improved on planets on nights with average seeing. And you just take off the mask on the odd night with perfect conditions (or when not viewing planets, of course). Costs nothing... must be worth a try at least?

1.25" only with that scope - but there is lots you can see with it with a range of 1.25" EPs or a zoom - don't think of it as a negative Sort out aligning using the finder and get a 8-25 or 7.1.21.5 zoom and you'll soon start making progress.

You should do the alignment using the finder, not an eyepiece and the main scope. The EP is only used once you get close using the finder.

Before considering buying more eyepieces, barlows or zooms I recommend you get to grips with what you have. Looking through a pin hole is astronomy. Yes you can get eyepieces with more glass and with easier eye placement.... but they all produce a tiny point image.... called an exit pupil. And they'll range from something below 1mm to something around 3mm. I recommend you point your telescope with your 8mm eyepiece at the moon and practise getting just the right eye placement to get the best image. You'll get better the more you try. Then you can point at other objects, learn your goto settings, see how they look with your 8mm EP, etc. Then you can come back here with more idea about what you might need to improve your kit... and the folks here can help you out. p.s. your scope is perfectly capable of getting wide field views. With the right eyepiece you can get around 1.7 degrees of sky at about 38x magnification.... you don't need more than that for many things in the sky.

https://www.cloudynights.com/topic/752053-omega-npb-versus-dgm-npb-whats-the-difference/ https://www.researchgate.net/publication/344786145_Omega_Optical_Improved_NPB_DGM_Filter https://stargazerslounge.com/topic/173662-lumicon-uhc-vs-dgm-npb-filter/?do=findComment&comment=2943504 My reading of this is that DGM came up with their filter spec in the 1990s and asked Omega Optics to make it for them. For a while (2015-16 or so) Omega tried to sell their own ‘improved’ version - using a very cheeky name and no doubt annoying DGM and their distributors. (or perhaps more likely someone was ripping off both DGM and Omega?) They now seem to be back in line - still making the one and only and original DGM NPB for DGM; and their own NPB that is now to a very different specification of their own. Whether you can find any of the ‘improved’ ones on the used market; and whether they really are any better; is debatable.

Excellent Never seen a shadow transit on M13 before.... ho ho ho.... I'll get my coat....

I could tell you needed a nudge in the right direction. 😂 (Although Don and Louis did all the heavy lifting.)

Search for 'Rubber O Ring'. They come in every imaginable diameter and thickness.

I tend to keep my observing eye closed when not at the eyepiece. And use only very dim red light head torch to keep the other eye fairly dark adapted when making eyepiece changes or finding new targets - including looking at SkySafari in night mode (on OLED display). Also, when I'm studying targets that benefit the most from full dark adaptation, I naturally tend to spend long periods at the eyepiece really studying it - so dark adaptation comes quite easily and stays for the duration because there are no distractions. Observing in a sitting position helps greatly too. And sketching what you are observing (closing observing eye when off the eyepiece) also helps to slow down the observing process and really take in what's on offer in the eyepiece. Observing sessions where I flit from one target to the next and only fleetingly (few minutes each) enjoy each one are really good fun too - but here I select targets where dark adaptation is less important and take less care to preserve it. (Although still only use dim red light and keep observing eye closed). I don't have any stray light from neighbours or streetlights to contend with - but if I did then I'd look into screens to block them and/or an observing hood.

and from the article you quoted above: "All monitors change over time, so calibration must be done on a regular basis. Most experts recommend doing it every few weeks to every few months." If you're fussy once you're probably fussy often. 🤔

I am not an imager and I have an out of the box (uncalibrated) monitor. Image 2 is showing more outer cloud than image 1 on my monitor for sure. But I'd still describe image 1 as better than image 2 - the sky is blacker and the stars sharper. I'm now wanting to calibrate my monitor... but how will films look after calibration?..... do the streaming sites provide footage that looks "best" on "out of the box" monitors? So maybe for a non imager like me "out of the box" is the place to stay?

I log all my visual observations in SkySafari and I like to include all the equipment I used for each observation - scope, diagonal, eyepiece, barlow, filter. SkySafari includes equipment placeholders for scope, eyepiece and barlow - but not diagonal and filter. I've got around the missing diagonal functionality by creating all combinations of scope + diagonal (that I use) in the scope section. So I select "scope+diagonal" in one go. I've got around the missing filter functionality by adding my filters as barlows with magnification 1x. So I select the "filter" used by adding the appropriately named barlow. Does anyone know if there is a 'proper' or 'better' way to do this? Or maybe there is a better observation logging tool that doesn't have these limitations?

UHC is not better or worse than OIII - they each work well on different target types. Having both in your bag is better than just one. I'm the same as you in that no filter is my preference most of the time.... but when the skies are dark and the exit pupil is large they really come to life and help bring out features not seen without them. I like my DGM NPB very much.

real work = downstairs playing with toys = upstairs