Shoot out! 102ED-R vs Tal 100RS

[RobertI]

Finally managed to get the new Altair Astro 102ED-R out alongside the Tal100RS for a comparison of ED versus achro performance. I've had some very helpful suggestions of targets for this comparison from fellow members and will be doing these over the coming weeks (and probably months!). But tonight the parget was Mars and fortunately seeing was excellent. Just for information the achro cost me £100 (used, not sure what the new equivalent would be now) and the ED cost me £900 (new), so an unfair comparison on the face of it! But the Tal has a good reputation so should be close for visual.  

The first difference was that focussing the Tal induced much more wobble than the shorter-tubed ED102-R, making fine focus more tricky. Also it was much easier to reach the slow motion controls when using the shorter ED-R.

The view of Mars through the ED-R was excellent, much better than in recent sessions with a clearly defined south pole, well defined dark areas along in southerm hemisphere and another dark region to one side of the top of the nothern hemisphere. At 200x plenty of detail visible in moments of calm. In the Tal at x200, the view was clearly not as good, with the maria looking much darker against the much redder looking disk, and the subtle detail not showing through so well. Also there was a red and blue fringing very apparent through the Tal - this may be due to the cheap prism diagonal used - I'll try and swap for a mirror for a better comparison. The purple halo was there, but subtle and only visible when I remembered to look for it!

Another plus for the ED-R it was that it was easier to see when Mars was in focus. But floaters were a bit of a problem in the ED-R at 200x  and strangely in the Tal at 200x, floaters were less of a problem despite the same exit pupil!

But overall the ED-R was a better experience all round, with better views and easier to handle.  However I am suspicious of the cheap prism diagonal in the Tal! Next instalment soon.

 

Edited September 14, 2020 by RobertI

[Fozzie]

Oooo think i'll follow this thread, looking forward to seeing your thoughts as the weeks progress.  

[Chris]

That's more like it, good to hear Robert! Following with interest

[RobertI]

3 hours ago, Fozzie said:

Oooo think i'll follow this thread, looking forward to seeing your thoughts as the weeks progress.  

I’ll try to make I as interesting as possible! 🙂

2 hours ago, Lockie said:

That's more like it, good to hear Robert! Following with interest

Yes, I think I was unlucky with the conditions for my first light(s) with the ED-R. Looking much better now. 👍

[Highburymark]

Nice report. What great value these 4” Altair EDs are! The FPL-51 is incredibly cheap, but this FPL53 version also very competitively priced at circa £900. Good to hear it’s performing well too.

[RobertI]

11 minutes ago, Highburymark said:

Nice report. What great value these 4” Altair EDs are! The FPL-51 is incredibly cheap, but this FPL53 version also very competitively priced at circa £900. Good to hear it’s performing well too.

Thanks Mark, yes the FPL-51 is very good value and would probably have been fine for my visual needs but I wanted to treat myself to the full fat version! 😁

[Alfian]

On 14/09/2020 at 08:41, RobertI said:

But floaters were a bit of a problem in the ED-R at 200x  and strangely in the Tal at 200x, floaters were less of a problem despite the same exit pupil!

This reminds a little of my experience with my Tal100r although in analysis it probably something completely different. I had a SW100ED and very nice it was too with beautifully sharp tight images, luna spectacularly so. I parted with the SW 100ED and got the Tal 100r (not a story for now).  Yes, the Tal has CA where the 100ED  didn't, but its not  sufficiently distracting to spoil things, however what immediately stood out was the Tals ability handle magnification.  With the 100ED I would inch things up to the point where resolution started to go, whereas the Tal  just seems to be up there (200x) more easily without any particular strain on the eyes. (eye)  Clearly this isn't a side by side, same seeing conditions comparison, but in terms of lasting impressions over time this is how I see it.  I don't have the scientific optical wherewithal to be able to explain what that amounts to in terms of the Tals optics but I'm not complaining.

[RobertI]

4 hours ago, Alfian said:

This reminds a little of my experience with my Tal100r although in analysis it probably something completely different. I had a SW100ED and very nice it was too with beautifully sharp tight images, luna spectacularly so. I parted with the SW 100ED and got the Tal 100r (not a story for now).  Yes, the Tal has CA where the 100ED  didn't, but its not  sufficiently distracting to spoil things, however what immediately stood out was the Tals ability handle magnification.  With the 100ED I would inch things up to the point where resolution started to go, whereas the Tal  just seems to be up there (200x) more easily without any particular strain on the eyes. (eye)  Clearly this isn't a side by side, same seeing conditions comparison, but in terms of lasting impressions over time this is how I see it.  I don't have the scientific optical wherewithal to be able to explain what that amounts to in terms of the Tals optics but I'm not complaining.

Interesting experiences Ian. I can’t think of an obvious reason either. I shall test this out on the moon where the eye strain at higher mags might be more obvious. I’ll let you know the result.