First light with C11 - Night vision and galaxies

[GavStar]

A good but cold club session this evening.

I have so far been focusing on nebulae with my night vision monoculars but tonight decided to experiment on getting more image scale for smaller objects including galaxies.

The critical factor with NV is to keep the setup as fast as possible to get as bright images as possible. Therefore to get more image scale, you need more aperture.

So tonight was my first light with my new C11, which has nearly two times the aperture of my previous biggest scope. Normally a slow f-ratio scope, I purchased an Alan Gee Telecompressor to speed it up to f5.9. Using a 55mm plossl afocally gives an f ratio of under 3 but with a magnification of 30, close to double what I normally use on NV.

The C11 and Alan gee worked beautifully together which was very pleasing since it was a bit of an experiment. There were no problems getting to focus and the star field was very flat. 

So starting first with my 6nm Ha filter, we went to Orion. Horsehead was clear but lacked some definition due to the moon. Monkeyhead was nice, nearly filling the fov. Both rosette and California were nice but too big for the smaller fov.

The real star of the show was M42/3. I had the best views ever of this stunning object. The nebulosity almost completed a full circle and the ‘fish head’ was photographic.

M46 showed the planetary nebula clearly. Eskimo was cool and fluffy.

After this a change of filter to a 685 IR pass for stars and galaxies.

M81,m82 both fitted well in fov. The lane across the middle of m82 was nice.

Leo triplet clear and only just fitted in fov. M51 showed its two eyes but no obvious spirals.

Then we changed eyepieces to 18 delite (giving 90x and f9) and 8 ethos (200x)

M81/M82 definitely enhanced with m82 filling most of the Fov with the 18 delite. 8 ethos was too much magnification - image was dimmer.

Next onto supernova 2018pv. Using the 18 delite we all agreed that we could make out the supernova as a small galaxy with what looked like two cores. Again ethos 8 was too dim.

Finished with m13 which resolved to the core despite having a low altitude.

So the C11 definitely adds a worthwhile extra option, but it seems to me that f ratio should be kept lower than 10, otherwise the dso become too dim due to the high f ratio. This gives a magnification limit of around 100x which I’m quite happy with.

 

 

[Demonperformer]

Great report, Gav.

Glad that the new scope is working out for you.

[alanjgreen]

Nice on Gavin.

If you get the blackening on m51 then on a better night it may show the arms. It's very condition dependent. From my old house, in my c11 I used to get the blackness between the arms but not the arms themselves (that was from outskirts of town).

Would be also good to note what you see of m51 in the c11 but without the NV fitted from the same location to judge the gain of the NV system over mark one eyeball ?

[Stu]

Nice one Gavin. Great to be able to view through your kit again, and pleased that the C11/Alan Gee combo works well.

On a moonless, transparent night I reckon the views will be pretty stunning. M42/43 was amazing even as it was.

Dark site trip needed soon!

[MarsG76]

Nicely written report.... NV.. the next step in observing?

 

[GavStar]

Here are two iPhone photos of m82 through the c11 from my v light polluted London garden. One is with NV, one without.

I was using the 18 delite to get 90x in both cases. So although NV is not as good on galaxies, it still makes a material difference.

[Demonperformer]

Still pretty impressive for "not as good"

[Stu]

Impressive, it does make a big difference. Nice detail.

[PeterW]

On 23/02/2018 at 20:29, MarsG76 said:

Nicely written report.... NV.. the next step in observing?

 

Sky and Telescope think so... going to have an article in the next few months. Actually people have been using them for over 15years, but availability and an awareness of how to use them to best effect has only come in the past 5 or so.

Peter

[Chris]

Congtratulations on your new C11! I think SCT's are a really versatile/compact for aperture scopes. I enjoy using my little C5 reduced to f/6.3 and will probably go down to f/3.3 for EAA. I bet you're the centre of attention at the moment at your club with these fantastic NV's, looking at your phone snap they do add a lot, so if they add even more on nebulae maybe these are the future! 

[MarsG76]

On 25/02/2018 at 12:30, GavStar said:

Here are two iPhone photos of m82 through the c11 from my v light polluted London garden. One is with NV, one without.

I was using the 18 delite to get 90x in both cases. So although NV is not as good on galaxies, it still makes a material difference.

Looks awesome...

does it look like you're looking through a real eyepiece, or does it look digital with LCD artifacts?

[Demonperformer]

Also, could you post a link to these? You state, about these, on another thread "its just like using a normal eyepiece, ie stick it in the diagonal and off you go." When I type "Night Vision monoculars" into google, I just get a load of sites that offer things that look like video cameras and I can't see how one would "stick it in the diagonal". Either I am finding the wrong thing, or completely lack imagination!

Thanks.

[GavStar]

46 minutes ago, Demonperformer said:

Also, could you post a link to these? You state, about these, on another thread "its just like using a normal eyepiece, ie stick it in the diagonal and off you go." When I type "Night Vision monoculars" into google, I just get a load of sites that offer things that look like video cameras and I can't see how one would "stick it in the diagonal". Either I am finding the wrong thing, or completely lack imagination!

Thanks.

Here’s a link to a televue page that has a photo of how it works (although it looks a bit silly using it on a tiny tv60 - looks more sensible when using a bigger scope ?)

http://www.televue.com/engine/TV3b_page.asp?id=36

[GavStar]

3 hours ago, MarsG76 said:

Looks awesome...

does it look like you're looking through a real eyepiece, or does it look digital with LCD artifacts?

Having adjustable gain on the monocular is really helpful here. You can adjust this to your particular preference. High gives a brighter image but some sparkling (scintillatation), lower gives darker image but to me looks just like views through a normal eyepiece. The photos I show are a very good representation of the view at the eyepiece - I think they look pretty natural.

[alanjgreen]

2 hours ago, Demonperformer said:

Also, could you post a link to these? You state, about these, on another thread "its just like using a normal eyepiece, ie stick it in the diagonal and off you go." When I type "Night Vision monoculars" into google, I just get a load of sites that offer things that look like video cameras and I can't see how one would "stick it in the diagonal". Either I am finding the wrong thing, or completely lack imagination!

Thanks.

Here is the kit you could use with your Televue eyepieces

https://www.actinblack.com/product/act-pvs-14/

https://tnvc.com/shop/tele-vue-tnvc-night-vision-afocal-astronomy-adapter/

 

if you are not in usa then you cannot buy the pvs-14 from there, it is illegal for them to export it. Of course, it's more expensive in Europe  

you can buy the Televue/tnvc adapter from usa and import that to uk. It's only available from tnvc  

(the adapter will connect to any Televue eyepiece that accepts dioptrx )

Then you need an Ha filter for nebula

https://www.widescreen-centre.co.uk/astronomy-filters-and-filter-wheels/astronimik-filters/astronomik-h-alpha-6nm

and an ir-pass filter for anything else (although I intend to try my Astronomik UHC first as it seems to have a suitable transmission curve. There's also a pro-planet 642 that I may try too)

https://www.widescreen-centre.co.uk/astronomy-filters-and-filter-wheels/baader-filters/baader-ir-pass-filter-685-nm

 

total cost for new kit, expect to pay £7000!

 

hth, Alan

[PeterW]

Or go second hand and pay a lot less, but not get the latest and greatest. The hunting fraternity are moving NV tondigital and thermal and so used gen3 does come up occasionally. The white phosphor and gain control is very nice, but you you still see things with older stuff.

The TNVC adapter connects a pvs14 to a televise eyepiece with a screw connection. You can just “poke it down the eyepiece”, for which a little 3D printing could help with the alignment. (Also helps with attaching filters in front of things too.

a 685nm filter is good for light pollution reduction... you can get camera lens filters cheaply. Going down to 640nm might sound like you get hydrogen alpha  as well as blocking... but you’re getting close to the pollution. If you want nebulae hit them with the narrowband filter,

otherwise a nice long 685nm for the broadband objects. Not sure how of the UHC filter profile, but not sure I’d bother.

@alanjgreen sounds like we might have another convert on this side of the pond?! I understand your skies are better than ours!

PEterW

[alanjgreen]

55 minutes ago, PeterW said:

otherwise a nice long 685nm for the broadband objects. Not sure how of the UHC filter profile, but not sure I’d bother.

The Astronomik UHC transmission

 

Seems to block all major artificial pollution and let >630nm through (similar to the pro-planet 642)

** As I already own one then makes sense to give it a go **

The 642 pro-planet ALSO seems to block above 860nm - I am not sure what is up there that we dont want? (Seeing?)

[Demonperformer]

3 hours ago, GavStar said:

Here’s a link to a televue page that has a photo of how it works (although it looks a bit silly using it on a tiny tv60 - looks more sensible when using a bigger scope ?)

http://www.televue.com/engine/TV3b_page.asp?id=36

Thanks, Gav.

Did a quick link through to their NV models = $2.5k upwards. Then would need the adapter ($56) and then would need to change all my eyepieces to TV ones. Thanks for the link - it is good to be able to visualise what is being discussed - but I think I will stick to imaging.

Thanks.

[Demonperformer]

1 hour ago, alanjgreen said:

Here is the kit you could use with your Televue eyepieces

If I had any ...

[Demonperformer]

47 minutes ago, PeterW said:

otherwise a nice long 685nm for the broadband objects.

I've tried various filters of the 'LP/UHC/UHC-E and goodness knows how many other acronym' variety. The only one I found to be really useful is a visual OIII, which is great for enhancing planetaries (but somewhat off OP's original topic - sorry!)

[PeterW]

Any eyepiece will do, just poke the unit into the eyehole. You can cobble an adapter to hold it centrally... though not nicely screwed in like the TNVC. For focal reduction you want as long a focal length as you can... there aren’t many options on the market.

Nothing lost from playing with eyepieces and filters you’ve already got.

Peter