New Takahashi Epsilon just arrived for visual NV use only

[GavStar]

Just arrived, now to unpack and decide if I will take it to our local astro club dark sky trip this evening...

Also came with an interesting Takahashi brochure in Japanese ?

 

[GavStar]

Shock horror - not triple boxed!! ?

[Pig]

LoL @ the triplet box ..... nice one all the same Gav ? enjoy.

[JeremyS]

Very nice GavStar. Will be interesting to see how it goes with NV.

What was in the empty space in the box on the rhs? Other Tak goodies?

[GavStar]

So this is definitely an experiment. Epsilons are primarily imaging scopes with a very fast f ratio, in the case of this 130d the f ratio is 3.3. This is great for imaging but also great for night vision monoculars which like having very fast f ratios to get as much light into the image intensifier as possible. 

However, the Epsilons can also be used for visual (although at f3.3 focusing could be interesting - a fine focuser add in is on the way).

An chap in the US on cloudynights is using an Epsilon 180 with night vision with great results so I thought I would give the smaller one a go. With my 40mm plossl I will get a near 4 degree fov (which I’ve found for NV a nice balance for many of the nebulae objects) and a fast f2 ratio. 

Looking forward to giving it a go (although hoping the collimation is pretty good as I’ve heard the Epsilons are right pains to collimate).

[GavStar]

4 minutes ago, JeremyS said:

Very nice GavStar. Will be interesting to see how it goes with NV.

What was in the empty space in the box on the rhs? Other Tak goodies?

Just an instruction manual, Tak stickers and Allen keys...

[PeterW]

Check you can mount it and plug stuff into it OK... then hurl it into the back of your truck and bring it along tonight. The more the merrier.. though I think you might need another mount.

Peter

[Stu]

Yep, you've got to bring it Gavin!

[PeterW]

.... no excuses...

[andrew s]

Interesting use for visual. You may find that at low power you can see the "hole" caused by the central obstruction as it can become similar in size to your eyes pupil. 

I found this year's ago when playing with a fast mirror and large diagonal.

Regards Andrew

[GavStar]

1 hour ago, andrew s said:

Interesting use for visual. You may find that at low power you can see the "hole" caused by the central obstruction as it can become similar in size to your eyes pupil. 

I found this year's ago when playing with a fast mirror and large diagonal.

Regards Andrew

I understand from that chap in the US that this isn’t a problem for Night Vision since the light is going into the intensifier rather than our eye and that can take an exit pupil up to 20mm but hopefully I will be able to verify that this evening...

[andrew s]

Quite right I did not spot you were using an image intensifier. I should have read your post with more care.

Regards Andrew

[PeterW]

@andrew s how fast and what sized obstruction... I am planning to get the scope made around an f3 mirror and have a choice of secondary, primary use with low power 7mm exit pupil... or NV

.Pete

[andrew s]

Hi Pete, it is only an issue if you directly use an eyepiece. In this case the size of the "hole" as it exits the  eyepiece is just the size of the obstruction / magnification. Where the magnification is the focal length of the telescope / focal length of the eyepiece. You want the size of the hole to be much smaller the the size of your pupil.

The hole is of course the the shadow of the secondary.

Hope this helps Andrew.

[PeterW]

How big is too big if we assume a 6-7mm exit pupil?

@GavStar how you getting on with the bolts?

Peterw

[andrew s]

I don't have a particular figure. I would go for less than a mm or two but this is just an educated guess. I have never seen an analysis but only a single example from my own experience.

Regards Andrew 

[GavStar]

5 hours ago, PeterW said:

 

@GavStar how you getting on with the bolts?

Peterw

They work great thank you! ???

And even provide a dovetail safety screw as well ?

I do regret not setting this scope up the other evening at Bignor - it would have been a lovely contrasting first light to Stu’s Sumerian Dob...

PS I hope I’ve got the focuser at the right end, these mirror thingys are so comfusing ?

[PeterW]

We don’t want things slipping and making grinding noises in the dark do we? 

So the 14 was a Stumarian was it ?

Peter

[Stu]

1 hour ago, PeterW said:

So the 14 was a Stumarian was it ?

Funnily enough my name on SGL was BigSumorian for a while

[GavStar]

Under the stars at last...(quite an eyepiece stack) Visual observing at f1.6

 

[PeterW]

Quite a handle to look out for as it whirls about! The eyepiece height was also perfect for you and almost constant is it moved around the sky. Very convenient, 

Peter

[GavStar]

53 minutes ago, PeterW said:

Quite a handle to look out for as it whirls about! The eyepiece height was also perfect for you and almost constant is it moved around the sky. Very convenient, 

Peter

After a slow start with this scope due to the various adapters needed, it’s great to be able to finally use it. Also nice to be able to add a 2 inch clicklock to enable my 55mm plossl to be used to increase the speed from f3.3 to f1.6.

Despite poor conditions (high cloud and heavy dew and LP!) we still managed to view the North America,  California, Pac-Man, monkeyhead, gamma Cygni, heart, soul, cocoon, and crescent nebulae. Looking forward to trying it against a slower refractor to see the impact of the very fast speed. Also nice that the single speed Tak focuser works fine at this high speed.

Quite amazing that we could view say the California at a Sqm 18.2 site through high cloud!!!