Solar White Light Imaging Rig

[iwatkins]

Hi All,

I don't usually post images of my kit, but I'm so pleased with this setup, thought I would.

Pictures below, but this is a standard NEQ6 with a handset extension cable.

Scope is my dream Lyra Optic 150mm f/8 (IStar glass). I've fitted a standard SW Motorfocuser, after making a custom bracket from ally, again on an extension cable. The scope in bare ally is perfect for white light solar. Even being outside all day on Saturday, the 1 wire button temp sensors I fitted internally and externally show the same temp difference all day long after initial cool down. There is even a cooling slot behind the counter cell to help cooling. All day long and the scope feels cool to the touch.

Then there is a Baader Cool Ceramic Herschel wedge, with a Baader T to C adaptor and a mono DMK41 camera. Camera is on an active USB extension. I usually run a BSC + 1.8ND + IR cut filters giving exposures of between 1/3333 and 1/5000 sec depending on conditions.

All those extensions plus 12v power means I can slew, focus and image from the comfort of my workshop. I have a proper (but really old) Windows XP machine in there. The difference having proper shade has to focusing is huge.

All the bits are great, but the OTA is just superb, not just for solar (why I bought it) but excellent at night. Yes, some CA on Venus, less so on the moon, but otherwise wonderful. If you are into fracs. and want something special but at not silly prices, talk to Glen at Lyra Optic.

Cheers

Ian

Rig:

Wedge + Camera:

Results:

[spaceboy]

VERY NICE INDEED!!!! How do those wedges work? Do you need protection for the scopes lens ? A blocker or Baader film ?

[iwatkins]

Not at all Spaceboy.

A Herschel wedge works by dumping around 95% of the energy straight out the back. Only 5% gets reflected upwards to the eyepiece. Still way too bright so you reduce it again to a 1/1000th by running a ND3.0 filter as a minimum before the EP for visual work.

For imaging you don't need quite so much filtering so you use say a ND1.8 filter to get very higher shutter speeds to capture those odd frames where seeing gets very good.

Combine that, say 1000 frames of video, with stacking software to extract the best 10% frames, you get a nice image.

The only downside of Herschel wedges, if you can call it that, is that you can only use them in standard refractors (well safely anyway). So it rules out Newts, SCTs, Maks etc.

Cheers

Ian

[John]

Thats a superb looking outfit Ian and those solar photos are outstanding

How do the visual views of the Sun compare with the images ?

[sgazer]

great stuff. How do Herschel wedges compare with something like Baader solar film?

[iwatkins]

Thanks John.

I always say imaging brings out the worst in a system and more so in solar with all the churn.

The human eye, or more correctly, the brain, is very good at dropping the "bad frames" from seeing, so you get a much sharper image in your consciousness.

Through the Baader Solar Continiuum filter, everything is bright green, but it brings the detail of the spots and granulation out very well.

You are not far from me John, if you want to drop by and try it, just shout. I'll even make a brew

Cheers

Ian

[iwatkins]

Sgazer,

Baader Solar Film is very good. Price vs. performance it is unbeatable by a long shot.

But as always, that last 10%, will cost you 100% more. Diminishing returns and all that.

I'll stress again, wedge is only safe in a refractor. But if I put an Astrozap Solar filter (cell with Baader ND5.0) over my 80ED, I get maybe ten seconds in every minute I can see granulation in our poor to average seeing in the UK.

Put the wedge in and drop the Astrozap filter, I would guess at 25 seconds in every minute.

It sounds a small difference, but it is very obvious for visual (my first love in all astronomy), and aids imaging in white light massively.

Yet again, Johninderby, is to blame for beans of toast in this household again this month

Cheers

Ian

[spaceboy]

Thanks for the info Ian. Is there no risk to the actual objective though? What I like with the Baader film is that it stops any excessive heat / direct sun light from hitting the optics. I know a lot of people do projection but I always assume this to be with cheapo scopes. I would be very reluctant to have a lens of expense open to the sun. Would this be needless over caution ?

[johninderby]

Yet again, Johninderby, is to blame for beans of toast in this household again this month

Cheers

Ian

mea maxima culpa

John

[ollypenrice]

I mainly use a Lunt Ha scope but I recently tried a Lunt Hershel wedge in a 4 inch apo and was simply astounded by the crispness and resolution, certainly better than acheived in a front filter whether Baader or glass. By all accounts the Baader Herschel is even better so I can feel an itch in the cheque book finger... You can't get baked beans here but I need to lose weight anyway...

Do you see the granulation in the Baader Herschel?

Olly

[spaceboy]

You can't get baked beans here but I need to lose weight anyway...

Olly

Some good news for you Olly. You can! If you search the web there is a fella who makes regular journeys over to France to deliver British food to those of you lucky enough to escape the great British weather. No sure how far down he travels though ??

[Viv]

Amazing result Ian.

I do hope you'll be at SGL8, so we can come & drool over it .........

[iwatkins]

Thanks for the info Ian. Is there no risk to the actual objective though? What I like with the Baader film is that it stops any excessive heat / direct sun light from hitting the optics. I know a lot of people do projection but I always assume this to be with cheapo scopes. I would be very reluctant to have a lens of expense open to the sun. Would this be needless over caution ?

As far as I can tell, there is no risk to the objective glass at all. It is after all just having the sunlight falling upon it. It is only when that light comes to focus at the other end of the OTA when it becomes concentrated.

Cheers

Ian

[iwatkins]

I mainly use a Lunt Ha scope but I recently tried a Lunt Hershel wedge in a 4 inch apo and was simply astounded by the crispness and resolution, certainly better than acheived in a front filter whether Baader or glass. By all accounts the Baader Herschel is even better so I can feel an itch in the cheque book finger... You can't get baked beans here but I need to lose weight anyway...

Do you see the granulation in the Baader Herschel?

Olly

Olly,

I'm sure we can sort you out with some tinned baked beans.

I can see granulation with it in my 80ED when seeing comes good, but is very passing and the image needs to be dulled slightly using one of ND filters on top of the ND3.0 and BSC.

In the 6" frac, the granulation is easy to see, even with slabs of bad seeing. Visually it is really excellent.

With a couple of adaptors, imaging is a breeze too.

Yes, the P version is expensive, and I was sceptical. But as white light visual and imaging is my "thing", it seemed to make sense. Once I got it, I was blown away. Worth every penny and wish I had done it much sooner.

If you do decide to build a solar observatory down there Olly, I would certainly recommend having this wedge in your arsenal and a good quality achromat. 6" would be about as big as I would go unless your daytime seeing can take more. But a set of aperture masks would also be very useful when seeing isn't so good.

Cheers

Ian

[iwatkins]

Amazing result Ian.

I do hope you'll be at SGL8, so we can come & drool over it .........

I've got a family wedding on that weekend, so won't be camping. But if the weather looks good on the Sunday, I plan to come over for the day and bring this rig for visual.

Cheers

Ian

[nightfisher]

Still think that is a superb scope, i so nearly bought it but not having an EQ6 stopped me, when are you going to post some lunar image`s from it

[iwatkins]

Jules,

I'll post some lunar images from it when I get to see the moon

I haven't seen the moon clearly since I got it, nor much else to be honest, what with the poor weather we've had recently

But don't worry, I'll get some shots up as soon as I get some.

Cheers

Ian

[JamesM]

Very impressive set up Ian and I am sure there must be plenty of polishing to keep off all of those finger prints. I think Istar are starting to become the next big thing with the choices and sizes they offer on their lens cell units. It has taken a while for the customer feedback to start rolling in, but now that the reports are good, I might have to get myself a nice 8" cell before the prices start to rise!

Like the images by the way and you have captured some great detail.

James

[iwatkins]

Thanks James

IStar make some nice optics, backed by test reports, but I think you are right, the costs will soar sharply, very quickly. And what Glen at Lyra Optic did with this set is truly excellent.

As for fingerprints, it isn't so bad. Another quick Autosol and a coat of Autoglym Supergloss Protection (silicon polish) seals it nicely. Emisivity is amazing. I've never had a scope that cooled faster than ambient before.

Cheers

Ian

[spaceboy]

Would this in a loose sense of the word "offer similar results" http://www.scopesnskies.com/prod/solar-observing/ac635.html ?

[spaceboy]

Never mind I just found this http://www.cloudynights.com/ubbarchive/showflat.php/Cat/0/Number/491390/page/0/view/collapsed/sb/5/o/all/fpart/all/vc/1