Explore Scientific 2" UHC Filter

[Relpet]

Back in the middle of August I started a post about 2" filters and got some very good advice.  After lengthy discussion I decided to buy the Explore Scientific UHC and was asked to make a report.

Dave in Vermont mentioned, without identifying the culprit, a manufacturer who made filters that did not necessarily screw into the standard thread properly.  I tried the filter in six different EPs from four different manufacturers and it was a perfect fit every time.

The filter is made in China and comes in a well designed outer box with a magnetic flap and sits in a padded plastic snap-shut container from which it is easily retrievable in the dark.  Every filter comes with its own test sheet.  I bought the filter from Bresser in Germany for €89 delivered to an address in France.

Since the filter arrived skies have been mostly cloudy.  On 28th August an almost full moon was shining through a thin veil of cloud.  It is not a lunar filter but I thought it would be worth a look and fitted it to a 25mm 2" ES EP. Anyone seeing the moon through this would have been convinced that granny (as usual) was right.  The moon is made of green cheese.  A green halo all around the disc and a fringe along the terminator.  All features on the moon less distinct, as experienced users would expect.

Using my super-duper new ES 2" 34mm EP, Antares looked distinctly more red with the filter - again as experienced users would expect.

Before I could proceed any further that night the cloud rolled in speedily from the Atlantic.  Game over.

There is currently advertised on TV some medication old people can buy to stop them getting up in the night to faire pi-pi.  It's not a frequent problem for me but twice this week I have got up at five in the morning and found the cloudless skies full of stars and dominated by Orion.  So I'll pass on the medication, thanks all the same!

The first morning there was still a sliver of waning crescent moon but I concentrated on using the 34mm ES with and without the filter on general starfields.  The brightest stars tended to turn green though the skies behind were noticeably darker.  The fainter stars failed to show.  This might be helpful if concentrating on observing dominant stars, though most observers would find these anyway.  Before I could proceed with a more specific target the night started turning to day and Orion was gradually washed out so all the dew-soaked paraphernalia was trolleyed back into the barn and I went back to bed.

This morning, totally against the forecast, Orion was again there in all its glory in a moonless cloudless sky but already the beginnings of a dawn lightening from the west.  Never having been able to track a nebula of any description yet but knowing where to look I trained the finderscope in the right area and found, after a few minutes, the Great Orion Nebula. That was when I decided to get my wife up!

While she was getting prepared I started with the 34mm ES, with and without filter.  Then the 25mm ES with and without.  Each time the nebula was clearer against a darker sky and the dominant stars much clearer.  The filter also seemed to counteract the increasing light from the west.

By this time my wife had joined me and was fascinated but I needed to go further in.  Switching to a 12mm Starguider 1.25" I was startled to see the Trapezium.  Then switched to a 5mm Starguider but that was a step too far.  The 7mm Skywatcher EP gave me the Trapezium in more detail but how I wished I had a UHC filter in that size because, by now, I could see - even as a novice - that it made a difference.  So it will be the same brand 1.25" going on my wish list.

Another poster said before that the packaging on this product is so good it's almost worth the money.  He may well say that - I couldn't possibly comment - but if it's a toss up between this and another product then you will be proud to have this on your shelf, as I am.  I look forward to clearer skies earlier in the night as autumn draws on and the search for more nebulae can go forward and I can get more mileage from this filter.

[michael.h.f.wilkinson]

Great report, thanks for posting. M42 does look much better in my (cheap and cheerful) UHC filter, I must say. Glad your first experiences are good. Try it on the fainter nebulae, you will be astonished at how much more you can make out with the filter

[astronymonkey]

Hi relpet,

Great write up and I agree that the box it came in looks like a work of art.

As for getting a 1.25 inch version, a lot of the 2inch to 1.25 inch adapters that you use in the focusser are threaded for filters meaning you can use the two inch ones with the smaller eyepieces rather than having to have both sizes.

Cheers

[John]

Sounds a good 1st light

Give it a go on the Veil Nebula while Cygnus is still high in the sky. As Michael says, UHC and O-III filters can make the difference between seeing something rather lovely and seeing nothing at all on some objects. They really earn their keep then !

[Relpet]

Great report, thanks for posting. M42 does look much better in my (cheap and cheerful) UHC filter, I must say. Glad your first experiences are good. Try it on the fainter nebulae, you will be astonished at how much more you can make out with the filter

Thanks Michael.  I'm even looking forward to seeing the Orion Nebula under a darker sky so relish the prospect of more pleasures to come.

Peter

[Relpet]

Hi relpet,

Great write up and I agree that the box it came in looks like a work of art.

As for getting a 1.25 inch version, a lot of the 2inch to 1.25 inch adapters that you use in the focusser are threaded for filters meaning you can use the two inch ones with the smaller eyepieces rather than having to have both sizes.

Cheers

Oh, Crikey!  Is there no end to the good advice I get from this forum?  I'll be in the barn at first light to see what's in my box.  Many thanks.

[Relpet]

Sounds a good 1st light

Give it a go on the Veil Nebula while Cygnus is still high in the sky. As Michael says, UHC and O-III filters can make the difference between seeing something rather lovely and seeing nothing at all on some objects. They really earn their keep then !

It was a sheer fluke that the sky was clear this morning and I was up to see it, john.  Skies for the next week not likely to be clear but I'll put the Veil Nebula at the list of top targets for the next clear night.  The purchase and report largely thanks to your engouragement, for which many thanks.

Peter

[Relpet]

Hi relpet,

Great write up and I agree that the box it came in looks like a work of art.

As for getting a 1.25 inch version, a lot of the 2inch to 1.25 inch adapters that you use in the focusser are threaded for filters meaning you can use the two inch ones with the smaller eyepieces rather than having to have both sizes.

Cheers

As you suggested I checked my adapter and, sure enough, the filter threads into the 2" barrel so making it suitable for both sizes of eyepiece.  This was such good advice and makes it possible for all my future filters to be based on the 2" size, in effect, BOGOF!

Sincere thanks,

Peter

[astronymonkey]

Good stuff, glad you found the screw thread and saved yourself a bit of money. The only thing to check is that none of your 1.25inch eyepieces have an end piece that is a bit to long so touch the filter when its fitted. Usually its ok butba few eyepieces have this issue depending on the length of the step down adapter piece.

Cheers

[Relpet]

Good stuff, glad you found the screw thread and saved yourself a bit of money. The only thing to check is that none of your 1.25inch eyepieces have an end piece that is a bit to long so touch the filter when its fitted. Usually its ok butba few eyepieces have this issue depending on the length of the step down adapter piece.

Cheers

Good advice again.  I dry-checked in the barn the EPs I'm most likely to want to use and the spacing was fine on all.  Clear skies this Thursday and Friday forecast so look forward to field testing.

[Bramble]

I am now in the market for a good general purpose filter and also need something usable for 2" and 1.25" eyepieces. I have a Moonlite focuser and I was contemplating threading the 2" filter on to the SCT end of my diagonal.  My Revelation diagonal seems to have a suitable thread.  Any thoughts? Also, has anyone had a chance to compare the ES UHC with the Orion Ultrablock?  Many thanks.

 

[Dave In Vermont]

What are you thinking of using a UHC-filter for?

Dave

[Bramble]

Everything really, although I appreciate there is no such thing as a perfect answer for all targets! However, being realistic, it is a question of finances so I would want to first add the filter that will give the most all round improvement for the greatest number of targets.  I really also want to understand the practicability of attaching a filter to a diagonal. Thanks.

[Stu]

6 minutes ago, Bramble said:

Everything really, although I appreciate there is no such thing as a perfect answer for all targets! However, being realistic, it is a question of finances so I would want to first add the filter that will give the most all round improvement for the greatest number of targets.  I really also want to understand the practicability of attaching a filter to a diagonal. Thanks.

I normally put my filters on the diagonal as it means you don't have to keep changing them when you change eyepieces. So if it fits in the front of yours, give it a go!

[John]

3 hours ago, Bramble said:

Everything really, although I appreciate there is no such thing as a perfect answer for all targets! However, being realistic, it is a question of finances so I would want to first add the filter that will give the most all round improvement for the greatest number of targets.  I really also want to understand the practicability of attaching a filter to a diagonal. Thanks.

The UHC and O-III filters only benefit nebulae and principally those that emit light in the wavelengths that the filters admit.

This report is often linked here proibably because it's still one of the best around on this topic:

http://www.prairieastronomyclub.org/resources/by-dave-knisely/filter-performance-comparisons-for-some-common-nebulae/

 

[Bramble]

Thanks for both these helpful replies.  It is a great report, of course, so it is definitely a UHC for me at present, just have to decide how many pennies to part with!

[Dave In Vermont]

I'll now give links for other useful filters to consider for both teasing out finer detail on different objects, filters of use in alleviating problems with certain types of light-pollution, and colour-filters found useful on the planets of our solar-system. I keep copies of these articles both in my computers - and even posted on my walls for use on nights I'm actively observing. Spares me from needing to boot-up a computer. And away we go.....

Another one written by Dave Knisely of the Prairie Astronomy Club:

http://www.prairieastronomyclub.org/resources/by-dave-knisely/useful-filters-for-viewing-deep-sky-objects/

And one addressing light-pollution by the Prairie Astronomy Club:

http://www.prairieastronomyclub.org/resources/by-dave-knisely/some-available-light-pollution-and-narrow-band-filters/

And, finally, one on useful (and less expensive) colour-filters for using for drawing out more detail on the planets of our solar-system, courtesy of Agena AstroProducts:

http://agenaastro.com/choosing-a-color-planetary-filter.html

 

Hope you enjoy these. I'm a certified 'Filter-Nut' and owner of over 35 different filters!

Dave

   

[Bramble]

Well I followed some of Dave Knisely's advise and I have purchased a DGN NPB as my first deep sky filter, purchased directly from the US. I am really looking forward to trying it out.  Thanks again.