26 replies to this topic

[BYoesle]

I have revised my report on the HelioStar 76 to include measurements made by Christian Viladrich.

 

Since it may be a couple of months or more before it can be placed in the Articles & Reviews section, I have uploaded it to a PDF file here.

 

Once it is posted in Articles & Reviews, I will remove the document and link to save room in my Dropbox account.

Edited by BYoesle, 25 June 2025 - 12:18 AM.

[paulhummerman]

Thanks for the careful and clear review - much appreciated!

[K.K]

That 0.25Å FWHM is incredible!
If the Heliostar 100 has an etalon with the same performance in a larger size, I’d buy it without hesitation.
Big thanks to Bob for the write-up and to Christian for the measurements!

[BYoesle]

Additional revision here.

 

[Helen P]

Are you going to review the Heliostar 100 ?

[BYoesle]

Hi Helen,

 

I have been told by SkyWatcher they would like to send me a review sample to evaluate.

 

Not sure when it might arrive, but my understanding is that it should be sometime before the fall.

[Dennissloan]

Congratulations Bob

[Wm Rison]

Tube ring thumbscrews.

 

The spacers are from McMaster-Carr

  Slotted Unthreaded Spacers
  Zinc-Plated Low-Carbon Steel, 9.5mm OD, 6.1 mm ID, 6 mm Long

Used 2 on each thumb screw.

 

Thumb screws from eBay

  M6 thread, 20mm length, 20mm head diameter.

 

William

Attached Thumbnails

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[3C286]

Bob 

 

Thank you for this tremendously informative review article of the Sky-Watcher Heliostar 76. The Heliostar is really tempting because Lunt scopes are at least 70% more expensive here in Europe...

 

I have a few questions:

 

Q1) In your review, you reported that you initially saw non-uniform contrast over the sun's full disc but this went away after the scope had warmed up for an hour. Is it your opinion that some of the early reports we were seeing on this forum were the result of not letting the scope come up to temperature and not due to early quality issues?

 

Q2) How does the warm-up time compare to other scopes like LS80 or LS60? I only have experience with my Coronado PST which seems to stabilise pretty quickly in 10-15 minutes or so. I do like being able to set up and go quickly so waiting an hour feel like a long time?

 

Q3) I understand that Christian Viladrich's lab measurements of the etalon that you mention were done under lab conditions. How does that tally with your field observation that the Heliostar 76 needs an hour under the sun to warm up and come up to performance? Are lab measurements at room temperature valid or am I misunderstanding things?

 

 

Thanks again for your in-depth review.

 

Tak

[ch-viladrich]

Q3) I understand that Christian Viladrich's lab measurements of the etalon that you mention were done under lab conditions. How does that tally with your field observation that the Heliostar 76 needs an hour under the sun to warm up and come up to performance? Are lab measurements at room temperature valid or am I misunderstanding things?

 

 

Thanks again for your in-depth review.

 

Tak

 

Hi Tak,

 

I measured the Heliostar during an annual solar gathering :

https://solarchatfor...pic.php?t=49745

 

It was pretty hot, maybe in the range of 32 to 35°C in the shadow. The Heliostar was in thermal equilibrium. It was out maybe one to two hours before I made the measurement.

 

 

 

[3C286]

Hi Tak,

 

I measured the Heliostar during an annual solar gathering :

https://solarchatfor...pic.php?t=49745

 

It was pretty hot, maybe in the range of 32 to 35°C in the shadow. The Heliostar was in thermal equilibrium. It was out maybe one to two hours before I made the measurement.

Hi Christian

 

Thank you for clearing up my confusion. I misunderstood your report -- I misunderstood that it was a lab measurement. It all makes sense now.

 

BTW: I loved reading through the thread you linked about JASON2025. A daytime star party north of Paris sounds like a lot of fun and very civilised. If it's near Paris, I might be able to persuade my wife to come with me one of these years .

 

Thanks

Tak 

Edited by 3C286, 28 June 2025 - 07:44 AM.

[BYoesle]

Hello Tak

 

Q1) Yes. My opinion based on my experience is that the early images of poor contrast uniformity were due to the HS76 not having thermally stabilized.

 

Q2) If the telescope is taken from an inside to outside environment with a significantly different temperature it takes longer to stabilize - I'd give it at least the recommended 30 minutes. This does take longer than say my grab & go Lunt 35 double stack.

 

If it has stabilized by already being outside at an ambient temperature, then it doesn't seem to take very long for it to be usable and the image is pretty uniform. My personal rule at that point is to wait for another 15 minutes after aiming at the sun for the etalon to settle in. YMMV.

[ch-viladrich]

Hi Christian

 

Thank you for clearing up my confusion. I misunderstood your report -- I misunderstood that it was a lab measurement. It all makes sense now.

 

BTW: I loved reading through the thread you linked about JASON2025. A daytime star party north of Paris sounds like a lot of fun and very civilised. If it's near Paris, I might be able to persuade my wife to come with me one of these years .

 

Thanks

Tak 

Hi Tak,

In odd years, the solar gathering is near Paris (JASON), and in even years, it is near Vichy (ROS).

[3C286]

Thank you Bob

 

Q1) Yes. My opinion based on my experience is that the early images of poor contrast uniformity were due to the HS76 not having thermally stabilized.

 

That gives me more confidence about picking up a used HelioStar 76 if one comes up for sale. I'd been put off by the negative early reports and had written it off so this is helpful.

 

Q2) If the telescope is taken from an inside to outside environment with a significantly different temperature it takes longer to stabilize - I'd give it at least the recommended 30 minutes. This does take longer than say my grab & go Lunt 35 double stack.

 

If it has stabilized by already being outside at an ambient temperature, then it doesn't seem to take very long for it to be usable and the image is pretty uniform. My personal rule at that point is to wait for another 15 minutes after aiming at the sun for the etalon to settle in. YMMV.

That's interesting. Before reading your article, I hadn't appreciated that larger H-alpha scopes take longer to thermally stabilise (but an obvious point in hindsight). I guess there's much to be said for the small H-alpha scopes like my PST for short solar sessions between work and daily life.

 

Thanks

Tak

[3C286]

Hi Tak,

In odd years, the solar gathering is near Paris (JASON), and in even years, it is near Vichy (ROS).

Hi Christian

 

Vichy's a little far for me. I hope to make it to JASON near Paris in 2027! Looks like a great event to have a look through different solar scopes and enjoy the sun.

 

Thanks

Tak

[Savage Henry]

Thank you Bob

 

 

That gives me more confidence about picking up a used HelioStar 76 if one comes up for sale. I'd been put off by the negative early reports and had written it off so this is helpful.

 

That's interesting. Before reading your article, I hadn't appreciated that larger H-alpha scopes take longer to thermally stabilise (but an obvious point in hindsight). I guess there's much to be said for the small H-alpha scopes like my PST for short solar sessions between work and daily life.

 

Thanks

Tak

Hi Tak, I just started any astronomy a year ago, and only started H Alpha 4 months ago, so take my opinions for what they are worth.

But after talking to folks here, and having 30 days to return it if I wasn’t happy, I bought the SW HelioStar/SolarQuest mount and tripod package when I found it under $3k here in the USA.

I put it next to my single stack Lunt 50mm for several viewings (I have only done VISUAL , no cameras beyond a phone) and knew I was keeping the 76. Also, I did the math on double stacking, upgraded BG, get the Crawford style focuser and fully trick out my Lunt, VS. also with the SW deal, I would be adding that GPS self tracking mount, and the 11.5 blocking filter for when I get a proper camera, and came down to about $500 more for the new scope, AND, also,

APERATURE is King.

It really does make a huge difference in many respects to detail and the EXPERIENCE…

Nothing bad to say about my Lunt, but once I saw the same view with 134% more area, it just blew me away.

Yes, I believe I am seeing what people complain about with the moving area of proper focus, AKA the Jacquinot spot.

But the view, using the tuner, and moving to off center in many cases, creates very much of a 3D feel, which I find incredible.

Edited by Savage Henry, 28 June 2025 - 12:58 PM.

[starcruiser]

 

I have been told by SkyWatcher they would like to send me a review sample to evaluate.

 

 

I would prefer that the instrument be purchased anonymously, if possible. They’re going to send you a perfectly QC’ed and possible even manufactured and fine-tuned specifically just for a review and thus may not be representative of the average sample that the public may get. 

 

I’m just skeptical of reviews based on samples sent by a manufacturer who knows it’s going to be reviewed. Buy it anonymously and just send it back. If offered for free in exchange for unbiased review, just send them receipt for refund.

[gstrumol]

I would prefer that the instrument be purchased anonymously, if possible. They’re going to send you a perfectly QC’ed and possible even manufactured and fine-tuned specifically just for a review and thus may not be representative of the average sample that the public may get. 

 

I’m just skeptical of reviews based on samples sent by a manufacturer who knows it’s going to be reviewed. Buy it anonymously and just send it back. If offered for free in exchange for unbiased review, just send them receipt for refund.

I have to agree with you. I believe there would be tremendous internal pressure to have a look at that particular scope and it's performance before shipping it out to a reviewer (and it would be naive to think they would not).

 

Think of a restaurant critic going to one for a review. He doesn't tell them when he's coming or what he'd be ordering before arriving there to make sure a 'special meal' wasn't prepared for him in the kitchen.

[BYoesle]

I would prefer that the instrument be purchased anonymously, if possible. They’re going to send you a perfectly QC’ed and possible even manufactured and fine-tuned specifically just for a review and thus may not be representative of the average sample that the public may get.

 

In a perfect world I agree - that would be great.

 

But the 100% cherry-picked assumption may equally be 100% incorrect.

 

While I don't know Kevin LeGore very well personally, he seems to be an honest and forthright person who assured me the HS76 that was sent was randomly selected off the shipping pallet as stated in my review, and it was in his interest that it would not be a "cherry picked" unit. My gut feeling is that Kevin saw there were a lot of H alpha beginners doing imaging with the HS76 and not following the acclimatization directions resulting in posting of horrible images. He therefore wanted someone to use the telescope that had more of a technical bent (apparently why he asked me to review the testing documents) and he was confident was familiar with H alpha systems and generally knows what s/he was doing.

 

By the crappy tape job on the box, it didn't look too cherry picked to begin with. The worst thing for both my reputation and SkyWatcher's would be that I was supplied a hand-selected unit that no other HS76 could match. That would become very apparent as others purchase the telescope.

 

So perhaps follow your own advice and get the HS76 for yourself. I'd love to see other experienced solar observers and imagers reviews.

 

With regard to the HS100, I'm now retired with a small pension and SSI for income. Send me $9,000 and I'll be happy to purchase it anonymously. Or you can purchase it and send it to me... PM me and we'll get 'er done. 

Edited by BYoesle, 29 June 2025 - 05:42 PM.

[3C286]

Hi Bob

 

I've re-read your excellent review again and if I may, I have another question about compatibility of the Heliostar 76 with binoviewers:

 

You mention in the article that "I would upgrade the focuser when doing serious imaging or when using a binoviewer -- for which the supplied focuser and/or OTA might also lack sufficient in-travel ability."

 

Did you get a chance to test the Heliostar 76 with binoviewers? If so, how limiting was it for your binoviewer and eyepieces? I've read on the internet, comments stating that the Heliostar 76 doesn't work with binoviewers but I gather from your article that it's not so black and white?

 

Would you use the Heliostar 76 out-of-the-box with binoviewers?

 

 

Thanks

Tak

[BYoesle]

Hello Tak,

 

My Baader/Celestron binoviewer uses no extender, and is a 2 Inch that needed the BF30 blocking filter. It would not reach anywhere near focus due to not enough in-travel. Other units may vary, but just using the HelioStar BF put an ordinary eyepiece very near the limit of in-travel, and is why I made the recommendation I did in the review.

[Savage Henry]

I used my Celestron 1 1/4” binoviewer with the supplied 1.8x attachment, and 30mm ep’s, and was able to get a focused view well within the range of the focuser.
This was the first time I tried a binoviewer and it filled my view to the extent that I will get their 40mm’s to try out next.

[3C286]

My Baader/Celestron binoviewer uses no extender, and is a 2 Inch that needed the BF30 blocking filter. It would not reach anywhere near focus due to not enough in-travel. Other units may vary, but just using the HelioStar BF put an ordinary eyepiece very near the limit of in-travel, and is why I made the recommendation I did in the review.

 

Thank you Bob

 

I see. So binoviewing with the HelioStar 76 is pretty much a NoGo... That does sound like a significant black mark against it (at least for me). Let's hope that Sky-Watcher takes up your recommendation to produce a Mk2 version of the HelioStar that's binoviewer-compatible.

 

I'd love to hear if any brave owners manage to successful lop off the OTA to an appropriate length.

 

Thanks

Tak

[EsaT]

That's interesting. Before reading your article, I hadn't appreciated that larger H-alpha scopes take longer to thermally stabilise (but an obvious point in hindsight). I guess there's much to be said for the small H-alpha scopes like my PST for short solar sessions between work and daily life.

Bigger objects always need longer time to reach thermal equilibrium with environment.

Courtesy of square-cube law.

 

Certainly one thing to take into consideration if I decide to pull the trigger of H-alpha telescope.

Still would be good to have decent resolving power to use higher than low magnifications.

(likely going to see sun through Coronado PST in annual hobby meeting)

 

But then again it's fall now and basically there's only one sunny day per weak, with the rest being either straight rainy or at least mostly cloudy.

So even if sun is technically above the horizon for 19h +change per day, there wouldn't be much to look at during time not eaten by work.

[BYoesle]

This will be the end of my review(s) of this telescope.

 

It was a cloudy and rainy 4th of July yesterday here in the Pacific Northwest, so I spent some time to process some additional images I've recently captured, and made some additions and finalized my observations of the HelioStar 76, which can be found here.

 

My comparison etalon system is not typical of what many if not most people would have, and my expectations and assessments are influenced by this. I hope I haven't been too analytical and a little nit-picky due to this, but that this also may result in additional improvements.

 

I also hope others will perform their own evaluations and form their own conclusions of this newcomer to the world of H alpha telescopes and can compare it to their existing H alpha telescope systems.

 

 

Click for larger.

 

Edited by BYoesle, 06 July 2025 - 11:20 AM.