Ags

I had no idea your 60 mm Tak was so big! Do you have any pictures of the Grubb?

Actually, it is a few euros cheaper than the EQ35M and EQ5 on this EU site: Equatorial mount GoTo / tracking (teleskop-spezialisten.de) Comparing the RA gears on the EQM-35 and the 55I EQM-35: 92.5 mm diameter and 180 teeth 55I: 73.4mm Diameter, 144 Teeth I think the 55I has the same gear as the regular EQ5 but I am not sure.

Ah yes, I am muddling EU and UK prices... This thing is priced in UK lower than an EU EQ5.

I managed to briefly test my charts in a fleeting clear and relatively moonless spell. I quickly reached the conclusion I needed to chart fainter stars. My previous catalogs didn't have good coverage of stars below magnitude 9, so I integrated a new catalog, and charted all stars down to magnitude 10, which is the magnitude that works for me. Besides anything deeper would have made the charts for too crowded to use. I also added a 1-degree field-of-view circle around the asteroid's point of maximum brightness. Increasing the depth of the charts immediately led to memory issues while building the book - Java could not allocate a large enough byte array for example, so I had to rework this and that. Looks like Vesta will put on a fine display in early May:

Next thread: how many do you use?

9, not counting the ones that don't count.

A new mount! Sky-Watcher EQ-AL55I PRO Go-To Astronomy Mount | First Light Optics Intrigued by this - same load as the EQ5 and EQ35M, but a lot cheaper and seemingly capable of Alt-Az mode too. Not too heavy. Is this the end of the EQ5?

Santa are you listening?????

Or maybe this... https://www.firstlightoptics.com/equatorial-astronomy-mounts/sky-watcher-eq-al55i-pro-go-to-astronomy-mount.html Ok it is goto, but I'll forgive it for that if it is any good!

I don't understand the issue often reported with scopes showing false color inside or outside of focus. Surely only the focus point counts? The false color inside and outside of focus is just intrinsic to being color-free at focus. If one lens in the lens cell introduces false color that is then corrected by a later lens in the lens group, then there MUST be chromatic aberration out of focus. It might be much less with an FPL53 or fluorite scope, but it must be there to some extent. But - why does it matter? No-one willingly looks at objects out of focus, right?

Yes, but not enough to affect a chart. The asteroid is beyond Mars, so if you place Earth in your mind's eye at the asteroid's location, it would only be a couple of dozen arcseconds in size, which would be the parallax observed by observers standing at our north and south poles.

I added 319 Leona as a test case, looks like I am matching the asteroid ephemeris to the field stars without issues as the Betelgeuse occultation is correct:

On the planet Vulcan EVERYONE has an 8-inch goto dob. On Earth things are more interesting.

I don't think the 4-inch rule is correct, it approximates another rule, which is the 50% rule. The next scope up needs to be 50% larger in aperture. So the step up from a 6-inch newt would be 9-10", and the next step up would be 14-16". For a refractor, the logical step up from my ZS66 was a 90mm refractor, and the next step would be 120-140mm.

The Baader would be nice for Luna though...

I am thinking about getting an Amici diagonal for certain kinds of star hopping (or, in my case, star hoping). But which one? They will all show the same diffracting pattern so is it worth spending more? Astro Essentials 90 Amici - £34 StellaMira 1.25" 90º Erecting Prism - £69 Baader T-2 90° Baader Astro Amici-Prism - £249 (prices courtesy of FLO) The Astro Essentials one sound like my kind of cheap and cheerful. Why is the StellaMira twice the price? The Baader is however attractive as I guess it really is better and the T2 connection means I can use it for short light path applications (my Askar FMA135).

I am moving over to use this mature cross-referenced derivation of the Tycho 2 catalog built by David Nash: http://astronexus.com/hyg It replaces my own collection of cross-referenced catalogs and increases the number of stars available for charting by a factor of about 20 - most of those stars are too faint to be usable directly but can be used in e.g. star field density mapping. For the zoomed in charts, I need to show fainter stars, based on my initial tests of those charts, I think down to mag. 10. To cope with the larger number of stars, I have added some multithreading to my process. There's an old joke about multithreading: A programmer who uses multithreading to solve one problem now problems two has.

@Paul M there's no place for romantics in this world, but I can certainly accommodate you on the overview charts! Regarding asteroid conjunctions - it is a good idea and one I can easily script. I will look at adding this to the book too. Likewise conjunctions with planets and bright Messiers.

I think it can be quite helpful to have an indication of how busy the star field is when chasing down something faint and star-like like an asteroid. If I realised a faint asteroid was tracking through a crowded field, I'd devote my observing time to something else. Thinking of making the fuzz red so it disappears with a red light torch.

Milky Way fuzz, a good thing or a bad thing in a star chart? I am always jealous of other star chart publications with Milky Way fuzz, this is my latest effort based on star densities from the Tycho 2 catalog (2.5 million stars). I need to cartoonify it a bit (make midtones darker, and dark tones less dark). Star clusters come out as very blocky fuzz, so I need to change the algorithm a bit...

With all this cloud, window shopping is the only way to enjoy this hobby

Want this NOW!!!!!!

I think that people naturally have different effective fields of view. We obviously don't see a dark circle at the edge of a our field of view, but there is a point at which things change from being comfortably in our field of view to being at the periphery, and I think I have a lot more periphery than many other people. So it's not surprising to me that I find my 50-degree SLVs to have a "widefield" feel, and I don't get a lot of wow from wider fields - they can be convenient but they feel like a lot of effort.

It was quite simple once I got started. I make jobs like these much bigger in my head, but in practice it was just removing 4 screws to open the case, unclipping a few wires, detaching the motor, cleaning and regreasing and putting it back together. I'll be a bit more positive about any future similar jobs.

Finished it tonight I cleaned and regreased the RA axis. I left DEC alone as I hardly use it. I took care to bend the red wire away from the RA gears. Put it back together and it still works. Next clear night we'll see it it's fixed.