Intes MCT180 solar use?

[Sergio Alessandrelli]

Hi to all

After some research I was able to found a second hand Intes Italia 7" MCT 180/1800 ota, to use it as deep sky/planetary visual telescope in my exits ad to take some deep sky pictures.
Now I adapted the 135mm Baader D-ERF I use with a WO FLT132 for the H-alpha. Resolution and contrast is lower than in the APO FLT132, but it is obvious because of the large obstruction resulting by the secondary mirror and the telescope diameter reduces at about 132mm by the ERF free diameter.
If possible, in the future, I'd like to go to a larger diameter solar telescope, but I'm not sure a 150mm acro/apo lens could provide so much better results for the cost. Even larger acromatic lens like a 200/230 are not for me (too long OTA, require heavy mount), and triband SCTs are too long focal length and ultra specialized OTA.

So... I could buy a Baader D-ERF 180mm to use the Intes full aperture.
What do you think about that? Could an MCT 180 f/10 with a full aperture D-ERF produce better results than my APO 132mm to justify the effort to buy a large D-ERF?

For the sun I use a Solar Spectrum SO1 0.5A so a telecentric 3X lens is necessary. Resulting focal length becomes problematic, but I could use the same ERF on the FLT 132 when seeing is not so good. I also have a Lunt CaK module. Altair Astro sell triband d-erf but I'm not sure it is safe for the Solar Spectrum filter to receive the CaK light collected by a such "large" diameter, and I'm not sure about the optically correctness of the MCT in that band. I could mount in parallel a smaller 63/840 acromatic lens I already have.

Thank you for your suggestion

Bye

[Valery]

1. Altair Astro sell triband d-erf but I'm not sure it is safe for the Solar Spectrum filter to receive the CaK light collected by a such "large" diameter,

2. I'm not sure about the optically correctness of the MCT in that band.

1. SS will work just fine with 3x or better 4x telecentric. You can add 35nm Baader H-a filter to completely eliminate any residual unwanted solar heat. 4x telecentric is better because of higher contrast of H-a details at F/40 light cone vs at F/30 cone.

2. MCT will work great at CaK line. Better to get Baader TZ3x telecentric as it is well corrected at 393nm.


Valery

[marktownley]

Valerys advice is spot on, as always!

[Sergio Alessandrelli]

1. Altair Astro sell triband d-erf but I'm not sure it is safe for the Solar Spectrum filter to receive the CaK light collected by a such "large" diameter,

2. I'm not sure about the optically correctness of the MCT in that band.

1. SS will work just fine with 3x or better 4x telecentric. You can add 35nm Baader H-a filter to completely eliminate any residual unwanted solar heat. 4x telecentric is better because of higher contrast of H-a details at F/40 light cone vs at F/30 cone.

2. MCT will work great at CaK line. Better to get Baader TZ3x telecentric as it is well corrected at 393nm.


Valery

Thank you Valery.

I hope I could buy a larger D-ERF in the future. Do you think I could use a Baader astrosolar ND 3.8 filter as ERF for the Lunt CaK module without reduce too much the light collected by the telescope?

[marktownley]

Hi Sergio.

No, this will not work.

Mark