Double stacking: return to factory?

[trwinship]

Hello all---what is the current recommendation for double-stacking a SolarMaxII 60 mm scope? Should the scope be returned to Coronado for optimization of the new etalon, or is this really not necessary? Thinking about doing this but have become a bit loathe to return the scope to Meade. Any experiences? Thank you!

[trwinship]

Well, answered my own question. Somewhat to my surprise, I got through to Meade customer service with no difficulty. And, they report that it is no longer necessary to return the scope to Meade if you double stack!

[colinsk]

There is no good answer. Likely you will do just fine. If you can try many double stacking filters you can do better. I think this idea ha become too expensive.

[markmanner]

Hi, I am also interested in getting a second Coronado SMII 90 to double stack on my new SMII90 filter set. Did they comment on why there is no longer a need to have them match the filters? Is it because the current SMII filters have a Richview tuner in both the primary and doublestacked unit?
Thanks for any info,

[trwinship]

Unfortunately I didn't really ask for details so I can't answer your question. But I'd recommend calling Meade customer service--the person I spoke with seemed to be well-informed about Coronado scopes and might be worth speaking to. Balance that against the reluctance Meade seems to have in speaking about the exact nature of the changes in Solarmax II and we might simply never know.

[markmanner]

Thanks, I am going to speak to someone at OPT as well. I understand they have experience with double stacking.
Did you decide to get the second unit?

[Merlin66]

I double stack two SM60 front etalons on an ED80.
The first came from a SolarMax 60 scope and the second was just the "normal" SM60 filter (with a BF15)
The only problem I had was sourcing the adaptor ring to get them to fit together.
Once I had this, there was no issues, no problems.
They have worked well for the past four years.

[markmanner]

I have heard that double stacking yields a noticeable improvement in contrast when used visually. I assume this would be the case for imaging as well, but to avoid an inappropriate assumption, could someone comment?
Thanks,

[Merlin66]

Mark,
I think you'll find when you look at the fantastic detailed images presented here that the majority have been taken with double stack set-ups.
The DS gives increased Ha resolution for both visual and imaging.

[markmanner]

I just spoke to OPT about it, and they confirmed two things. One, Coronado/Meade don't offer double stack matching service any longer, but do say that the pre-SolarMaxII units should be matched. Second, because the SMII units, main and second stack, both have a Tmax tilt wheel and the Richview tuner, no factory matching is required. Tuning real-time on the scope is ok.

[trwinship]

No, I haven't gotten the second etalon yet--almost $900 is not in my budget at the moment. But it's still on my radar as the "Next Big Thing." After spending a couple of days comparing views with other observers, mostly PST users, I feel like I still have a ways to go before really maxing out the viewing potential of the single-stacked 60 mm SMII. This was particularly true when I was observing (Aug 18, 1600 UT) a visibly moving solar flare near the limb of the sun that was nearly invisible in a couple of PSTs that were also present.

[colinsk]

Mark,

Do you now what exactly Richview tuning is?

[JohnW]

Is it safe to order a double stacked unit and have it posted thru the mail? Are they rigid enough to suffer no damage?? Thanks.

[markmanner]

Is it safe to order a double stacked unit and have it posted thru the mail? Are they rigid enough to suffer no damage?? Thanks.

The SolarMax and Solarscope double stacked units come unattached in separate foam receptacals. I imagine the Lunt ones do as well. They can still get damaged in transit, but it won't be because it happens to be a double stack unit.

[markmanner]

Mark,

Do you now what exactly Richview tuning is?

Hi Colin, no, it is unclear. The materials that come with the SMII just say, 'use Tmax tilt to adjust brightness and eliminate reflections, and RichView tuner for best detail and contrast'.
In looking at the way it operates, it is hard to tell what it is doing, but by rotating the outer ring it may be changing the relative positions or spacing of the etalons? What does the Lunt pressure tuner do? Does it alter the spacing of the etalons?

[trwinship]

I don't know what's going on either, but it's something interesting: when I look down through the objective lens of my SMII I can see two slightly overlapping discs mid-tube which change position slightly as the Richview lever is rotated (I'm almost afraid to describe this for fear that my scope is defective--images are fine, though). Also of interest, though unknown significance, is that if I look though the diagonal/BF without an eyepiece I see two red unfocused solar discs--quite unlike the original SolarMax. As I said, though, with an eyepiece there is a single, well-focused contrasty image. Hope that's what I'm supposed to be seeing!

[marktownley]

when I look down through the objective lens of my SMII I can see two slightly overlapping discs mid-tube which change position slightly as the Richview lever is rotated (I'm almost afraid to describe this for fear that my scope is defective--images are fine, though).

Coronado external etalons have a central spacer between the etalon plates, and this sits in a central area of the etalon plates that is uncoated. To stop light passing through this central uncoated area (and spacer) is a peice of stick on aluminuim type foil - this foil is oversize compared to the central uncoated spot and appears to have been stuck on inaccurately by 'eye'. Soooo, if you rotate to external etalons with respect to each other the 2 central foil spots change their relative positions slightly to each other, which is what you are seeing...

Regards what Richview tuning is, based on this description and others I have read it seems to me that it is just a TMax tuner system that you are able to rotate to allow the hinge axis of the TMax's to be clocked to afford the best view. It's nothing new; myself, Bob Yoesle and others were modding our old (original) double stacked SMxx etalons by rotating them with repsect to each other to minimise banding issues way back in the cloudy night days several years ago before the SMIIs emerged on the market.

Accurately respotting the aluminuim foil is a mod to do that can increase image contrast, results depending on how 'skew' the aluminuim spots are...

[Merlin66]

Mark, et al,
I understand your description of the Richview tuner operation, but....
would that apply to a single stage configuration??
I believe the Richview comes with all SMII both single and double stack??

[markmanner]

Mark, et al,
I understand your description of the Richview tuner operation, but....
would that apply to a single stage configuration??
I believe the Richview comes with all SMII both single and double stack??

The single stage SMII 90 I have has both the Tmax tuner and the RichView tuner, so I think it does apply to both single and double.

[trwinship]

Actually, Mark, I'm looking down through the objective of my single-stacked SMII 60 mm--there is no external etalon. However, your description of the two foil discs slightly overlapping does match what I see. Do SMII scopes actually have two internal etalons? Coronado does advertise much improved image contrast over the original SolarMax, which seems to be true.

[trwinship]

[

The single stage SMII 90 I have has both the Tmax tuner and the RichView tuner, so I think it does apply to both single and double.

I'm a bit confused here--I don't have a SMII 90 but the SMII instruction booklet shows the 90mm, single stacked, as having only the Richview tuner.

[markmanner]

[

The single stage SMII 90 I have has both the Tmax tuner and the RichView tuner, so I think it does apply to both single and double.

I'm a bit confused here--I don't have a SMII 90 but the SMII instruction booklet shows the 90mm, single stacked, as having only the Richview tuner.

Hi, the confusion I think arises from the SM 90 we are talking about. The single stack dedicated SMII 90 telescope has the etalon internal, and a RichView tuner on the side of the OTA near the eyepiece. The SMII90 filter set that you use on an existing refractor (or use as a double stack unit on the SMII90 telescope), has both a Tmax tuner and RichView tuner. See pic above.

[trwinship]

Ah, thanks! Now I understand.

[markmanner]

On the topic of double stacking, I received the adapter to connect the SM90 units to my refractor today. This of course brought complete overcast from the hurricane overhead, but I did set up the telescope (clouds visible in the background).
Pic for those interested.