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A 150 mm Achromat and a 120 mm Apo, a personal review.
by John Baars

Performance of and differences between a 150mm widefield achromat and a 120mm apochromat. A personal review. Apple and pears are both fruit. Comparisons between the two are normally not done. Different taste, shape and bite. Still, we do it all the time. Consumers know the differences. Why bother for...
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For some reason when I pull up the review the screen has a black background and it's difficult to read the text... any ideas?
Thank you, John.

Same here. When I submit the black version of TSS, it becomes readable. I'll ask.

[Edit: can't be helped at this time, sorry. It will become beter readable when you turn to the black version of TSS]

Well, black background or not, I squinted through it Very nice, John! It was quite an interesting read; definitely some points to ponder.

Thanks again and all the best,

No problem reading, John. Nice comparison....thanks for doing and sharing!!

Dave

Excellent comparison, based on a long time experience with the telescopes!!!

Thank you John for sharing,
JG

Very interesting read. Thanks!

A very good article John, thank you for taking the time to do this.

Got it John.
Thank you for this great review!

Very interesting article John!

Great data presentation!

Like Jg said, you know these scopes intimately.

Thanks, and very nice article!

Hello John. A superlative comparison and analysis report. I knew going in that the chromatic aberration would be an issue. To my knowledge, there are 6 of us on this forum here using a 6" class achromatic refractor. You and JG use the SkyWatcher branded 150 f/5. Bigzmey (Andrey) and I use the Celestron branded 150 f/5. Don Quixote (Mark) and Helicon (Michael) use the Explore Scientific 152 f/6.5. They work great on the moon, until you get near the limb, and then the chromatic aberration sets in, and the planets look like a kaleidoscope. But wait, we use these for the beautiful wide field, high contrast, and sharp views on the DSO's (faint fuzzies). Most of us have another more suitable telescope that we can use for planetary work. Thanks for your great comprehensive report John, and the very best of regards.

Thanks John: great comparison: well done!!! As you say, it is pretty much as expected, especially with planetary and lunar views in the apo: but it is great to have a more in-depth analysis.

Marshall, I also have the Celestron 150 f5 achro. Great for widefield and faint fuzzy views on a budget. I would love to have an Esprit 150 or the Evostar 150, but I couldn't justify it without selling my TSA102: and that isn't going to happen; so my achro has to satisfy my lust for size- and it does it surprisingly well.

Keep up the good work John, and happy viewing.

- Dean

Useful review, too often there is a default to the most technical solution. However, there are always compromises in every solution. As shown here.

Nice review, thanks. I selected the text with my mouse so the black background shows as white text on royal blue.

DeanD wrote: ↑Mon Apr 27, 2020 11:35 am Marshall, I also have the Celestron 150 f5 achro. Great for widefield and faint fuzzy views on a budget. I would love to have an Esprit 150 or the Evostar 150, but I couldn't justify it without selling my TSA102: and that isn't going to happen; so my achro has to satisfy my lust for size- and it does it surprisingly well.
- Dean

Hi Dean. I am sorry that I missed you in the group. Well, that makes 7 of us now. I really enjoy my XLT150R refractor, as it is easy to carry out, setup, and a joy to use. This Fraunhofer doublet refractor does a great job on the faint fuzzies for the cost. A scope this size in a ED or APO version is way out of my price range, especially since I am retired now. Thanks for reminding me Dean, and the very best of regards.

We should open 150ST club!

Excellent review John! Matches my experience to the letter. 150ST is my favorite scope for open clusters, large nebulae and low power walks along the Milky Way. It is also riches surprisingly deep on faint galaxies, even though I now have bigger guns for that.

Smaller APO/ED scopes my favorite tools for doubles and casual planet/Moon observing.

When I want to go deep for faint galaxies or high resolution on planets/Moon, I roll my large SCT out.

Thanks for the review John. 6" Achros despite some of the weaknesses, are excellent scopes for general observing. My 6" frac is out almost every clear night.

It is definitely a very interesting read . Thanks for posting it.

helicon wrote: ↑Mon May 18, 2020 2:50 pm Thanks for the review John. 6" Achros despite some of the weaknesses, are excellent scopes for general observing. My 6" frac is out almost every clear night.

Well, now I count 8 of us using this variety of telescope.

Makuser wrote: ↑Tue May 19, 2020 7:10 pm

helicon wrote: ↑Mon May 18, 2020 2:50 pm Thanks for the review John. 6" Achros despite some of the weaknesses, are excellent scopes for general observing. My 6" frac is out almost every clear night.

Well, now I count 8 of us using this variety of telescope.

Everyone should have it. A great performer in amazingly compact and lightweight package.