Recommended Telescope to capture Full Solar Disc with Quark

[keramos]

Hi All,

Are there any recommendations for a Telescope that might enable me to capture full Solar Disc with Quark and ASI174MM.

I was thinking of purchasing a reducer of some sort but if I get another scope I'll be happier.

Thanks in advance.

[vlaiv]

Let's do some maths

Assumptions:

Quark has x4.2 barlow so any FL will be multiplied with this factor

ASI174 has 5.86um pixels and 1200 pixels in vertical direction, so lets say that you need to fit the Sun in 1000x1000 pixels (to have some room to spare for both image size and calculations to be on the safe side).

Sun smaller than 33' in diameter so we can take this upper limit. That gives us 1980" to spread over 1000 pixels or resolution of 1.98"/pixel

So this is our starting point. Which focal length gives resolution of 1.98"/pixel at 5.86um pixel size. Simple formula gives that it is: ~610mm FL

Now this is complete FL not the FL of the scope, so we need to divide this with barlow mag factor - and we end up with:  145mm FL.

So even if you throw aggressive focal reducer into the mix (something like x0.5) you still need very small FL - something below 300mm FL - don't think you are going to find suitable scope in this range.

Possible other options:

1. Get camera with larger chip size (don't know what could be suitable, maybe ASI1600MM if price is not prohibitive - and do the math)

2. Get scope with smaller FL - something like 50mm F/6 in range of 300mm and do mosaics of 4-9 segments to cover full Sun disk - this you can try with your ED80 - it will need more mosaic segments, and I don't know how much image changes over time, but if you do for example 25 segments (5x5 mosaic) with movies of 1m - this will add up to a half an hour of imaging (with moving between mosaic tiles and stuff) - If surface detail does not change much in this time than it is ok, but if stuff moves in lets say 5-10mins then you will not have consistent image.

3. I might be wrong with maths above, so I urge others to review and point out any errors that have been made.

[Davey-T]

I think that the Quark is best suited to close ups which it excels at, also mosaics with the faster frame rate the better.

For full discs one of the Lunt solar scopes is easier.

Dave

[keramos]

Thanks vlaiv/Dave,

I guess I'll save up and get a Lunt

Just have to wait a bit...

[Grotemobile]

http://www.daystarfilters.com/COMBOQuark.shtml

They now do this one, for longer f/l scopes. 

[Owmuchonomy]

Examples of a Lunt 60 and ASI174 here: