Sketches & Belated Updates: Mars, Morning DSOs, and Last Light for the XLT 150.

 I've kind of dropped the ball with my blog this week. Here's a few updates, and some sketches too.

2020-October-5 - 12:20 AM.

I set up my 6" Dob to take a good look at Mars and the Moon. Between clouds and haze, they popped in and out of visibility during the time I was out, but I did get some very nice views.

Mars was absolutely amazing. I think I said every positive word in my vocabulary when I first looked at the thing. The seeing was very good, and Mars was a crisp orange disk with very obvious dark smudges. I observed it first at 200x with my 6mm Kellner, and I observed it at 240x and 300x as well. I even attempted to go a little above max power to test empty magnification for the first time. It seemed to look about as good as 300x--not actually worse, but not really better. About what I expected.

I reproduced the surface features I could see in the drawing. I could see the horn of Syrtis Major, the equatorial belt of Sinus Meridiani, and after consulting maps, I could see a subtle light spot where Hellas Basin was. Seems that the albedo patterns shift subtly over time--right now Hellas basin is nothing like a circular/elliptical feature, it's very irregular.

the Moon. This is not the full disk, only a small part of the Moon.

 I also looked at the Moon. Messier & Messier A, my favorite lunar craters, were very well lit at this phase. I sketched them (the two elongated craters at center, near the terminator) and the surrounding terrain, but I didn't finish the part of the drawing far from the terminator.

That was all I observed that night, and it was well enough. Mars was truly excellent and the Moon was very nice too, and by the time I was done I was tired and ready to go to bed.

2020-October-6 05:00 AM

I went out observing with my Mom, who I insisted look at Mars during the close approach week. Late night didn't work for her, so we woke up early and went out to the star field to look at some winter DSOs, as well as the Moon & Mars.

Mom used the FirstScope, and found Venus, the Moon, and I believe the Pleiades as well, iirc.

We looked at Mars, M42 & M43, The star cluster surrounding Tau Canis Majoris (one of my favorites), the double star Castor, and I took a look at Messier 41, finding it to be a very pleasant and enjoyable cluster, easy to find. Mom started to feel ill, so she stayed in the car most of the time. (I stress though, that it was her decision to stay out.) I went back over some of the objects I'd looked at to take a few sketches.

M42 was very excellent, and is always a treat and a beauty to behold. I put a high power eyepiece in to get a closer look at the Trapezium, but was pleasantly surprised to find that the view of the entire nebula became better. It was certainly dimmer, but there was more structure visible than the aesthetically pleasing, bright low-power view. I didn't have time to reproduce the high power view in my sketch.

Mars was not very good, unfortunately. Mom liked it, but the seeing wasn't very good and it was only getting lower in the sky. I'm gonna take my whole family out when Mars is better placed and the seeing is good so they can all see it in all of (or nearly all of) its glory. It was nice to see a different face on Mars than the usual (Mars' nearly identical rotation period to Earth's means that it shows the same hemisphere at the same hours from night to night)

Page of log entry for October 6th AM. DSO colors inverted.

2020-October-6-PM: Last Light for the Omni XLT 150.

I had been meaning to getting around to comparing the Omni XLT 150 equatorial-mounted Newtonian and the Apertura DT6 Dobsonian for a while now. I wanted to know which one to keep, and which one I should sell, so that I can afford a 10" dobsonian. My 6" dob has served me very well but a small dob might be more redundant with a big dob compared to a small eq-mounted newt compared to a big dob. I wanted to make sure the Omni XLT 150 could replace the 6" Dob for the weeks or months it would take for a 10" dob to arrive.

I have used the Omni XLT 150 probably five times, and I think maybe once I actually had my log out. Whenever I have the XLT150 out I find that, even though I'm testing things and it'd be helpful to keep a log of what's going on, I'm just too exhausted to deal with it and the log. This is a red flag.

The equatorial mount really is excellent, though keeping it balanced exactly right is more difficult than a dob. Worse, though, is that the ergonomics of an equatorial-mounted Newtonian are really just not it. Constantly having to rotate the scope in its tube rings, trying to find a good eyepiece position where the finderscope remains usable, it's just too much. While observing the other night with this telescope, I found it just exhausting to use.

Sky conditions weren't perfect, which seems to be a curse with this telescope (or because i can take out the dob more often and get to those rare, perfect conditions), but they were at least pretty good. I tested it on Jupiter, Saturn, and Mars, as well as the Double Cluster, Pleiades, and the Blue Snowball (NGC 7662), which I found for the first time using this scope.

I didn't record anything in my log, but I did type a brief report of finding the Blue Snowball in the chat for the astronomy club channel on my Discord server:

I found the blue snowball
If it did have color it was very very subtle
Not how i remember it from the observatory
To find out, find this weird angly bit between Shedir & Scheat, and use a star chart to hop from asterism to asterism a degree or so until you get to it
It was impossible to distinguish from a star at 23x, but at 50x and 125x it was clearly nonstellar
At 300x it was dim but i could glimpse a subtle hollowed middle
(All this with a 6" scope in mediocre skies)

I will definitely be revisiting this object and giving it a proper sketch. My description might make it sound like I didn't enjoy it--maybe that was because I was frustrated a bit-- though using the telescope all in one part of the sky isn't that bad, once you've got it balanced and the eyepiece is in a good place.

The planetary performance really was not as good as that of the dob. But I think I know why--when I cleaned the mirror I tightened the mirror clips down too much, which I didn't realize would pinch and subtly deform the figure of the mirror. It may look like solid glass, but as John Dobson said, "you're only allowed to bend by one one-thousandth the width of a saran wrap." I loosened the mirror clips and it should be a closer match now, though I haven't tested it.

Deep Sky wise, the performance between the two telescopes was nearly identical. I didn't have any exact matches for magnification, but I tried to get it close in the trials between the two telescopes, and I'm fairly sure the differences I was seeing were purely down to small differences in magnification.

Towards the end of the night, I noticed that there was dew on the secondary mirrors of both telescopes, and so I will have to be sure to acquire or make a dew shield for my Dobsonian. The primaries were both dew-free. What was remarkable was how well they worked with fog over the secondary mirror--the view was certainly worse than it should have been, but I could still see through it.

By the time I was getting ready to pack up, I could see the Moon coming up over the trees, and Mars was high enough in the sky for me to do some serious observing. Seeing was pretty good, though not as good as it was on the 5th AM. I didn't get my log book, but I wish I had, as it was quite pretty.

The lady and gentleman who own the property I observe on stopped by towards the very end of my viewing session. It was the first time I'd met them in person. I let them look at Mars and the Moon. I used the 32 or 25mm Plossl and the 5x Barlow, which provides a very long eye relief, so they didn't need to get close enough to accidentally touch the telescope. While finding the Double Cluster for them, I found the ET Cluster (Owl Cluster/NGC 457) instead and let them look at that. ET Cluster was on the list of things to look for, so I need to (re)learn how to star-hop to it and do a proper sketch of it some time soon. It's a very nice cluster.

The optics of the XLT150 were very nice, and noticeably better than before I cleaned the mirror. I didn't end up using the wide-field, high-surface brightness near-minimum-power of the XLT150 with the 32mm Plossl much while observing, except as an aid for manual star-hopping as a sort of super-finderscope. But I just really hated the ergonomics of it. I found myself really wishing I could keep just the mount (which was new, and works very well!) and trade the newt for a 4" refractor, or maybe a Cassegrain, which would have a much more easy to use eyepiece position.

I had been at this point seriously considering selling the XLT150 instead of the 6" Dob. While packing up, I stupidly took the counterweights off before the telescope OTA. It swung back, the counterweight shaft swung forward, and it jabbed me in the chest. It took a few moments of shouting in pain, holding the unbalanced telescope up, before I could continue. "Yep," I said, "I'm selling you."

And thus my trial run became Last Light (for me) for the Omni XLT 150. Not a bad telescope at all, just not a good fit for me.

And so the next day I put the XLT 150 up on craigslist for $300, and have now got a buyer, who is upgrading from the truly awful PowerSeeker 127EQ.

It's been cloudy all week, so I haven't been able to do any astronomy since the 6th. But hey, Mars opposition is tomorrow, and despite the fact that tonight, someone in the triad is going to be getting a new piece of astronomy equipment, it seems like triad skies will be clear tomorrow night.