Sunspot 2726, Big Prom, Full Disc | 150mm & 40mm HA | Nov 13th 2018

[MalVeauX]

Heya,

Well, I missed the beautiful grand arching prom from yesterday. It's mostly decayed and gone now barely a full day later. Alas. But there are still two fairly bright large prominences on the limb and a fairly small but interesting designated sunspot with a visible umbra and I think cycle 24 polarity. It seems to have grown considerably since yesterday. Maybe it will continue to be interesting if it lasts another few days towards the limb (love limb spots!). It was all cloudy and rained this morning. I sat in my observatory and waited out the rain, waited out the clouds, and eventually had a few minutes between a few big rain clouds that were moving quickly to grab data. The seeing was decent despite all the cloud movement, around 11:30 Eastern Time.

B&W:













Colored:













Earth Scales:

EarthScale01.jpg (77.73 KiB) Viewed 1145 times

EarthScale02.jpg (60.74 KiB) Viewed 1145 times

EarthScale03.jpg (84.24 KiB) Viewed 1145 times

Sky Conditions & Waiting for the Sun!

skyconditions_11132018.jpg (10.89 KiB) Viewed 1145 times

SolarSetup02_11132018.jpg (60.72 KiB) Viewed 1145 times

Celestron 150mm F8 Refractor > Daystar 150mm ERF > Baader UV/IR Block > Quark Chromosphere > ASi174MM
PST > 1.5x Barlow > ASi174MM

Very best,

[ffellah]

A series of great shots, Marty. Very nice detail in the proms and the active area close-ups.

Franco

[Montana]

Persistence pays off Marty, these are great the poor chilly little girl, I hope you gave her a hot chocolate after

Alexandra

[krakatoa1883]

Excellent work, Marty. Why don't you insert a focal reducer before the camera ? It would help to obtain a larger view.

[MalVeauX]

Thanks all,

Why don't you insert a focal reducer before the camera ? It would help to obtain a larger view.

I do sometimes, especially when seeing doesn't support the large scale. These are ~F35 (F8.3 scope with 4.2x telecentric in the Quark) and the seeing supported it, so I just ran with it. It's a bit oversampled for the pixels, ASI174MM. But the alternative is to drop to F17~F18 and be very undersampled, which is often better between the two choices. Just didn't do it that morning.

Very best,

[Carbon60]

Very nice images, Marty.

Stu.

[MapleRidge]

These are really great captures Marty, thanks for sharing

More cloud, snow and cold here the past week...might see the sun on the weekend according to the forecast. I see your assistant is bundled up a bit more, so you must be getting cooler as well.

Brian

[Valery]

Thanks all,

Why don't you insert a focal reducer before the camera ? It would help to obtain a larger view.

I do sometimes, especially when seeing doesn't support the large scale. These are ~F35 (F8.3 scope with 4.2x telecentric in the Quark) and the seeing supported it, so I just ran with it. It's a bit oversampled for the pixels, ASI174MM. But the alternative is to drop to F17~F18 and be very undersampled, which is often better between the two choices. Just didn't do it that morning.

Very best,

Hi Marty,

The advice to use a focal reducer is correct. Just use it with 2x shorter barrel. I got three different barrels for my GSO 0,5x reducer.
With my main instrument with F/10, I can get F/21, F/25-26 and F/28-29. No need to use F/D higher than F/28-29.
Oversampling leads to exposure increasing, S/N reducing, FOV decreasing overall look worsening. Only losses.
F/17-20 is much better for prominences where you need as better S/N as possible and as shorter exposure as possible.

Hope this helps.


Valery

[MalVeauX]

Could you link what sort of shorter barrel being referred to? I'd like to try it out. F21, F25 would be great!

Very best,

[Valery]

Could you link what sort of shorter barrel being referred to? I'd like to try it out. F21, F25 would be great!

Very best,

These shorter barrels are custom made (by a local machinist) with the same threads as the original abbrrel but with shorter bodies.

The barrel has at it's front side the thread for the reducer and at the back end it has a thread as C-mount camera has.
The bodies length are: 12mm and 18mm.

Hope this helps.


Valery

[krakatoa1883]

You should determine by yourself what is the reducing factor for a given distance from the converging lens to the camera sensor. It's enough to point the scope to a distant object and see how larger becomes the field of view with the reducer.

There are actually different reducers available for use with the Quark

05x.jpg (30.93 KiB) Viewed 999 times

the left one (GSO or TS) is the weaker, the right one is much stronger although both have the same reducing factor printed on the barrel. This number is only a very rough approximation. I use both depending on the situation.

Quark chromosphere has been designed particularly for short f.l. refractors, with longer ones as yours the Combo version would be a much better choice.

[MalVeauX]

Thanks! Interesting.

I do need to go back to using my 0.5x focal reducer and experiment some more.

Very best,

[eroel]

Marty:
Super cold beautiful session.
Best regards,
Eric.

[marktownley]

Brilliant set of images Marty!