Ags

ION engines send their exhaust out at really high velocity. I'm not entirely sure the the Iodine would remain in orbit or would escape into space. Being ionized, Earth's magnetic field would also play a role. A little Googling says Earth escape velocity is 11 km per second, while ion engines shoot out ions at 15 to 100 km per second.

After a busy weekend, 25 doubles to go...

Hello again!

The Moon is way too bright tonight for me, and dominating the section of sky I have access to, so I had a quick look at the Moon and packed up. At least the Moon let me confirm I can reach infinity focus with the the SLV 6 and NPL 20 in the Q Turret, but not with the NPL 30. I then realized that being shortsighted, I could simply put my glasses on - focus reached in all three eyepieces! Moon looked good. I was particularly struck by one large crater on the terminator in the south with high walls and a large central peak - the peak was casting a shadow not only along the ground, but up the crater wall facing the Sun.

I wonder if it would really be that much better than a good old ST80 and a nice 24mm 68 degree eyepiece?

Trying something new tonight: Zenithstar 66 with a Baader Q Turret and 20mm and 6mm eyepieces. The sky is not fully dark yet but I did a quick system check on the Double Cluster. It turns out I barely have enough infocus for the NPL 20mm given the optical length of the turret - the stars snapped into focus in with no drawtube left, the diagonal was right up against the focusser. Fortunately the SLV 6mm requires a little less infocus, and I hope the other eyepieces I have bought for the turret (NLV 9 and 12mm) will be the same. The only solution I can think of would be to get a prism diagonal , so I hope the other eyepieces will be ok! The Double Cluster was washed out given the residual daylight, hope it stays clear. The turret seemed ok by the way - I gave up on it a while back because it was a bit stiff and the cheap diagonal I was using it with coudn't grip the turret well enough and tended to disassemble mid-rotation anyway. The new TS dielectric diagonal seems much more solid, and I also tried loosening the turret a little.

I have been told by retailers there's no difference except for color. The C6 SLT is a relatively good price, shame the mount is a waste. I use my C6 (AstroFi version purchased as OTA only) with an AZ GTi.

I realize I managed to mention every eyepiece I own except one...the oldest piece in my collection, the Speers WALER 10/82, does not seem to play any role at all...hmmm. Can't sell it though, as it has a case of Lens Rattle.

I'm betting three reasons: weight, weight, and weight.

Hard to answer as I have many different observing moods and very different telescopes and targets. My ES 20/68 is used all the time, but that is because it is used in my finderscope, except when it is replaced by the venerable Super 25 when I want to save weight for scope balance issues. In the Zenithstar 66, my most used piece is currently the Speers WALER 4.9/82. It combines wide field with the highest native magnification in my eyepiece case, so very suitable for doubles and many DSOs. But it might be supplanted by a barlowed ES 6.7/82 if that gives a sharper view. The ES 6.7 is already preferred for solar work as it is substantially sharper than the Speers WALER. But if I need a bigger exit pupil or I am looking at huge DSOs like the Pleiades, the ES 20/68 is the eyepiece of choice, or alternately the Speers WALER 13.4/82. If I am in a nostalgic mood, the ultrawides are relegated in favor of the NPL 20/50 and SLV 6/45 as those give views in the ZS66 reminscent of my childhood. In the C6 for DSOs, it is a toss-up between the Speers WALER 13.4/82 and the ES 20/68. But for planetary and lunar views it would be my "zoom eyepiece": a Baader turret with NPL 20/50, NLV 12/50, NLV 9/50 and SLV 6/45. The NPL 30/50 might substitute in for the NPL 20/50 for lunar viewing however. Pick just three from those! It is Solomon's choice! I would have to pick the ES 20/68, ES 6.7/82 and Speers WALER 13.4/82.

A great looking scope. Definitely one I am thinking about.

Only 36 doubles left to document for the Southern Hemisphere edition... which means there are only 36 doubles left to document for the all-sky edition 😀

I think the SLVs are a nice option in a small telescope. The SLV 6mm gives about 0.7 degrees FOV in my ZS66 with an exit pupil of 1mm, which is perfect for viewing DSOs in that scope. The 9mm NLV I have coming from Mr Spock (alarmingly the avatar shows the Mirror Spock, equipped with an Agonizer!!!!) should give a slighty brighter and wider view, also ideal in the ZS66. In a larger scope, the SLVs become more specialist planetary eyepieces as the FOV of course becomes very narrow.

I use a Wratten #8 to deal with atmospheric dispersion with some success, so I think it would work quite well for CA.

Had a brief look at the Moon last night with my 12x60 bins, now I have a way of getting the IPD right - it only took 40 years of trying! The bins gave a lovely 3D effect to the Moon.

The binoculars now appear to be aligned correctly. I didn't adjust anything, just showed the bins the screwdriver and it got its act together sharpish! Guess it wasn't collimation, I just struggle on an epic level with setting the IPD. I had to get that right before I started collimating, so I tried taking off my glasses and using them as a template for spreading the eyepieces. Having done that I got a lovely 3D view of the Moon, which was also much steadier as I was using the correct holding technique shared by @BinocularSky recently.

My dog has learnt squeaky toys come in Amazon boxes. Every parcel gets a thorough inspection now.

Don't forget an eyepiece case full of twenty essential eyepieces!

I do wonder why I have so many eyepieces, when my modus operandi is to pick one for the evening.

Yes, but for DSOs the extra size is quite useful, and a bigger sensor always helps with the Moon.

Having completed my eyepiece set I have only two visual astronomy items left on my wish list - a Nadira and a good manual AZ mount. Sadly the perfect lightweight AZ mount with high capacity and slow motion controls has yet to be invented!

Thanks, I want to like these binoculars, but I have only been able to use them as a very heavy monocular. By the way the video was for the Skymaster 15x70, but the screws are in the same place. Setting up the binoculars and backing off 20 cm makes sense and I will try that.

You are a good salesperson, but a leetle Tak is beyond my reach. I have been thinking of a bigger 90-100mm ED scope, having enjoyed the ZS66 so much. I don't know how much I would appreciate the Tak perfection. We had the briefest session tonight looking at the Moon through my 50mm finder scope. My partner (post cataract operation) instantly saw the bright yellow-green rim around Luna from the CA of the scope, but this was invisible to me - possibly because I still have my natural, aging brown-tinted eye lenses. But it does suggest I don't need to spend on a Tak!

The big difference this year has been getting a 50mm RACI finder, and combining it with proper research for observing sessions, by which I mean I wrote a book with all the targets I wanted to see! They work together perfectly for me, giving much richer and more organized sessions. But the new approach does seem to have increased cloud cover... I also got a petite Zenithstar 66 which has been revolutionary in its fun factor. The C6 has spent a lot of time sat in a corner while I have been outside having adventures with the little frac.

I am proud to say I have the complete set of Type 3s! 🤣