An August clear sky beckons ......

[jock1958]

1 hour ago, Stu said:

2" will certainly give you a wider FOV but you will struggle with the DL due to its longer focal length. The DC is just on the limit really, ideally you need about 650mm focal length or less to be comfortable. John's lovely Vixen is f6.5 and that does it nicely, my Genesis is f5 so is even wider.

These charts show the DL, DC and Genesis with first a 24mm Panoptic (1.25") second a 30mm 82 degree ES (2"), the third one is a 41mm Panoptic (2") and finally a 56mm Plossl (2"). In each one, the DL is the inner circle, DC mid and Genesis outer circle. So you can see the DL is always going to struggle, with the Plossl giving the same field of view as the 41mm but with a larger exit pupil (6.2mm) which may help when filtering with an OIII under dark skies. It is certainly the cheapest way to start experimenting!

So, you will get wider with 2", but it may be simpler to get a different scope with a shorter focal length although you would still need the 2" eyepiece.

What can I say Stu,  many, many thanks. Will take me a bit of time to absorb the info but pictures paint a thousand words 😃👍

[John]

23 hours ago, jock1958 said:

Thanks Stu for your input. As I've only got 1.25" eyepieces and diagonal for my Tak 100DL, will I need to step up to a 2" diagonal & a 30mm + eyepiece to achieve 3.5 or more degrees?

The widest I've got with my Tak 100 DL is 3.1 degrees using a 40mm 70 degree eyepiece in the 2 inch fitting which is not quite wide enough to squeeze in the E & W segements of the Veil nebula. I rarely use my DL with 2 inch eyepieces though probably because, as Stu says, my Vixen 102 ED F/6.5 is a more useful wide field scope.

 

[jock1958]

24 minutes ago, John said:

The widest I've got with my Tak 100 DL is 3.1 degrees using a 40mm 70 degree eyepiece in the 2 inch fitting which is not quite wide enough to squeeze in the E & W segements of the Veil nebula. I rarely use my DL with 2 inch eyepieces though probably because, as Stu says, my Vixen 102 ED F/6.5 is a more useful wide field scope.

 

Thanks John. Might take Stu’s advice with the least expensive option and experiment with a 56mm plossl with a view to eventually buying a wider field travel scope. 

 

[John]

The 56mm plossl will show you as much sky as a 2 inch eyepiece can (as does my 40mm / 68 degree) but the background sky might be a bit washed out because of the lower magnification. Worth trying though to get a feel of the max field that a scope can show.

My favourite "big field" combo is my Vixen 102 F/6.5 and my Nagler 31mm. 3.8 degree true field but a little more magnification to darken the background sky a bit more.

I have a totally clear forecast for tonight and no moon until the early hours so I think I'll get the Vixen 102 and the 12 inch dob setup side by side and compare the views of the Veil with those

[jock1958]

20 minutes ago, John said:

The 56mm plossl will show you as much sky as a 2 inch eyepiece can (as does my 40mm / 68 degree) but the background sky might be a bit washed out because of the lower magnification. Worth trying though to get a feel of the max field that a scope can show.

My favourite "big field" combo is my Vixen 102 F/6.5 and my Nagler 31mm. 3.8 degree true field but a little more magnification to darken the background sky a bit more.

I have a totally clear forecast for tonight and no moon until the early hours so I think I'll get the Vixen 102 and the 12 inch dob setup side by side and compare the views of the Veil with those

Good luck and fingers crossed for tonight. I had high hopes last night after a beautiful day but it clouded over as soon as it got dark! 

Edited August 25, 2019 by jock1958

[John]

3 hours ago, jock1958 said:

Good luck and fingers crossed for tonight. I had high hopes last night after a beautiful day but it clouded over as soon as it got dark! 

Thanks - Last night was no go here too. I didn't even set a scope up.