Friday, November 6, 2015

So, You Want To Learn About Nebula Filters?


Just when I thought I'd already read everything there was to read about nebula filters...I just came across this Site today - For all intents and purposes, and as far as I can tell, this is "The Granddaddy" of all Web pages on nebular filters!

And, I just wanted to share it, right away.
Wow! Amazing stuff! I have no idea why I never came across it before?
I strongly suggest you check-out all of the (extremely informative!) Links.

Also, I've always been a huge Fan of the light pollution filters made by Omega Optical (I usually order them from DGM Optics). If interested, check-out This great PDF document (found via the "Mega-Nebula Filter Site" linked to above).

----- I'd like to take this opportunity, to just briefly mention a new must-have book!
I'll write a full Review of it here, for the blog, in the near future. -----
So, just the bare minimum for now:

I'm very happy to report, that Rony De Laet, an amatuer Astronomer who's work I've greatly admired for many years - Has written a book! 'The Casual Sky Observer's Guide'
I bought (the electronic version of) it immediately! And, I simply love it!
I highly recommend it! (Hopefully, Santa Claus will bring me a paper version of the book for Christmas?)

I have been following his impressive, and very inspiring Website for many years...
Besides the fact, that the Author is obviously a binocular fanatic (like me!) -- He also produces amazing and inspiring pencil sketches! Using Binocs, of course!

In a nutshell: What impresses me most, is his minimalist approach in regards to equipment.
He has been able to do all of this, mainly with just two pairs of binoculars. Two pairs, of what many amateur Astronomers might consider modest binocular models. In other words, not "Alpha" model or super-expensive units.
A pair of 8x56's and a pair of 15x70's (along with a SkyWindow mirror mount).
Very inspiring.

It is basically something that I would love to be able to do: Choose just two pairs of binoculars, to be used for any and all observing (and sketching).
In fact, I'm working on doing just that...
I've always seemed to be spending too much time comparing the performance of various binoculars -- Instead of simply investing in two good pairs, and using them (instead of always scrutinizing their optical abilities).

To be continued...

Incidentally, I've noticed that The SkyWindow looks like it's available for order
once again - The Website was undergoing renovations for a while there... 

Clear skies!

Friday, October 30, 2015

VHT Nebula Filters From DGM Optics

The VHT Nebula Filters from DGM Optics - First impressions

Just a short Post, for now.

You can see the full line of (1.25") nebula filters available, from DGM Optics Here Of course, they are also available for 2" eyepieces.

As I mentioned in my previous Post: The pair of Garrett Optical 100mm binoculars were in need of some nebula filters...More specifically, the pair of (stock) 1.25" eyepieces needed filters. And, I wasn't 100% sure which types I would go with, this time around. These binoculars are much larger than any pair I've used before.

I was originally thinking: A pair of (1.25") GCE's (again)... Unless, (I thought to myself) after consulting Dan: He might suggest something different this time? Perhaps NPB's? I was anxious to find out.
Well, I did ask Dan (of DGM Optics [via e-mail]) and he recommended The VHT's. And it made a lot of sense to me. Here's a Link to the Info page, for the various filters.

Here is the transmission curve, from Omega Optical, the manufacturer: 



Also, from Omega Optical's Site regarding The VHT's:

"An excellent Nebula filter for smaller scopes (4-6 inches aperture) where light gathering and throughput are at a premium. It is also quite effective with larger scopes."

I have been very intrigued, with the measured spectral information shown here on DGM's page. The white graph on the lower right is of GCE Filter.
I also can't help wondering exactly what the measured spectral results would be, for my actual filters. That would be neat.

I haven't had many nights of good seeing, in which to thoroughly test them - But so far, the VHT's have been able to boost the contrast, on the few nebulae that I've tried them on.

And, finally, for astrophotographers - Here are some examples of how these filters help when imaging.
You'll see links to some Reviews of DGM nebula filters Here.

I plan to post a short Review of these filters here, in the near future.

Clear skies!

Tuesday, September 22, 2015

The Bortle Scale - Route 6 In Cortlandt NY -

The Bortle Scale - Bright suburban skies, and Route 6 In Cortlandt NY -

   Image credit: created with the free software Stellarium, retrieved from Sky & Telescope.

I'm happy to report a short, but successful "mini-field-trip" to Cortlandt New York, courtesy of my BIL, Nelson. It was the first outing for my recently acquired Binocs:

The Garrett Optical 100mm binocular telescope
-and-
The New 12x60 handhelds, from Oberwerk.

Nelson enjoyed, and remarked about the abundant FOV in the 12x60's (compared to the narrow FOV of the big Garrett's). 

Among the objects observed, were: 
M31 - The Andromeda Galaxy
M33 - The Pinwheel Galaxy
The Double Cluster in Perseus -
(NGC 869 [h Persei] and NGC 884 [Chi Persei])

And, The Milky Way looked great!

I went ahead, and set-up Google Earth, as was described on the very interesting (if somewhat eclectic Page) Here

According to this neat new map - My local skies, here at home, are:

Bortle 6   Bright suburban sky 5.1-5.5
  • the zodiacal light is invisible
  • light pollution makes the sky within 35° of the horizon glows grayish white
  • clouds anywhere in the sky appear fairly bright
  • surroundings are easily visible
  • the Milky Way is only visible near the zenith
  • M33 is not visible, M31 is modestly apparent
  • limiting magnitude with 12.5" reflector is 14.5

If this overlay technique is accurate, then my local light pollution is just about as "good" (maybe even half a magnitude better) than I had originally guesstimated. And I'm really happy about that...

If this is in fact, the case - Then I'll take it! I can work with 'Bright suburban sky'

What this all actually translates into now, for me...Is that I will (eventually) have to confirm this map's accuracy. By "manually" checking the naked-eye visibility of several different constellations / stars, etc.

According to this map, the skies (which I thought were awesome) during a recent Astro-outing, in Cortlandt New York, are:


Bortle 5   Suburban sky 5.6–6.0
  • only hints of zodiacal light are seen on the best nights in autumn and spring
  • light pollution is visible in most, if not all, directions
  • clouds are noticeably brighter than the sky
  • the Milky Way is very weak or invisible near the horizon, and looks washed out overhead
  • limiting magnitude with 12.5" reflector is 15
 Clear skies!

Saturday, September 19, 2015

Finally: A Binocular Telescope!

I'm very happy to have "picked up" visual Astronomy observing again.

F/5.3 100mm Garrett Optical

I finally managed to get a nice pair of (early model) Garrett 100mm Binocs. And, I'm going to need a new pair of nebula filters for them.
I was shopping around, just looking, etc. 
But, it didn't take long for me to realize, that I'd be best off with a pair from DGM Optics! Duh!

So, my next Post, will be about the selection and use of nebula filters for this instrument...
Along with a short review.

Clear skies!

Sunday, September 13, 2015

Visual Observing Has Commenced Once Again!

I'm very happy to be posting on this blog once again...

Thanks to the generosity (and Herculean effort) of two very dear Friends - I'm now the proud owner, of my very own 8" Cat (SCT Telescope).
A rare, Bausch & Lomb 8001 Schmidt-Cassegrain, with (sidereal) motor drive.

The complete restoration, and collimation of the optics, is still a work in progress...
The first few phases have been completed -

Below is a quick Pic of the telescope.


In the meantime, I've started observing/sketching again (using my Barska 15x70's); and having a lot of fun!
 
 Clear Skies!