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alanjgreen

Understanding “a-focal” observing with Night Vision (Revised)

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Time does not stand still...

It has been 17 months since I wrote the original version of the above named article and there have been a few changes in the intervening time period…

1.       I now have 17 months more a-focal experience of using a telescope with a night vision device attached directly to the eyepiece.

2.       A new forum has been created for the discussion of such “Electronic Assisted” observing equipment on this website.

So I decided to revise my article and post it in this new “most applicable” forum.

Let us start with the basics…

 

What is a-focal observing?

“a-focal observing” simply means that the night vision device is attached directly to an eyepiece (after the focal point of the telescope). You are placing the night vision device’s objective at the exit pupil point in the light path.

The easiest way to achieve this is the use the “TNV-14 Eyepiece Adapter” (available from Tele Vue). This adapter has threads on either side to connect (1) any Dioptrx accepting Tele Vue eyepiece to (2) a PVS-14 Night Vision device.

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

tnvc3.jpg.206b80e343d4398970095e8173e6bb0b.jpg

Here is a picture of a Tele Vue 55mm Plossl connected to a PVS-14 using the TNV-14 adapter.

tnvc55mm.jpg.9c6584765408f21602203dca0b57c0e1.jpg

To perform “a-focal” observing we need to simply insert this “stack” into any telescope focuser. If the attached eyepiece can achieve focus then there will be a focused image available to view in the PVS-14.

 

Here we see the stack attached to my 20” dobsonian and my 107mm Borg refractor…

dob3.jpg.3a29ecc9b0a8e94758d8201d3a7f5808.jpg

107-3.jpg.b86b679a39f47af6c377402be47386ef.jpg

 

What are the advantages of a-focal?

The biggest advantage is that you WILL be able to reach focus in any scope. Unlike other options you are simply placing the night vision at the point of the exit pupil. For Newtonians, this is a big point.

 

Fundamentals of a-focal observing.

Now we are past the basics, we have some slight more complicated “fundamentals” to get our heads around…

1. The PVS-14 night vision device is designed to work at a focal ratio of f1.2 (which is very fast). To get the most from the device then we need to aim to send light from the eyepiece as fast as possible to take maximum advantage of the night vision device. A faster focal ratio results in a brighter image, a slower focal ratio results in a dimmer image.

- Here we have been given a “lucky break”. Because the PVS-14 has an effective focal length of around 26mm, if we use any eyepiece with a focal length greater than 26mm then the “effective” focal ratio of our system gets “magically” increased.

[I will show how we calculate this effective focal ratio shortly but think of this on a par with adding a focal reducer into the light train].

Unfortunately, any eyepiece with a focal length less than 26mm will decrease this “effective” focal ratio of our system.

 

2. The PVS-14 has a fixed forty (40) degree field of view. It does not matter how wide field our eyepiece is, the night vision device will only ever show the centre forty degrees. This means that you don’t need 100 degree Ethos or 82 degree Nagler eyepieces, narrower field of view Plossl, Panoptics & DeLite’s will be fine.

- Again, don’t panic! There will be so much to see in the forty degrees that it will feel like 100 degrees. I have come from 100 degree eyepieces and I have never once wondered where my huge FOV went :)

 3. Eyepiece eye relief is important. You need eyepieces with enough eye relief to match the distance from the top lens surface of the eyepiece to the position of the night vision objective lens. Too much or too little eye relief will result in loss or distortion to the outer edges.

 

What is the minimum set of eyepieces that I need?

I use a total of four (4) Tele Vue eyepieces with my Night Vision device:

1.       Tele Vue 55mm Plossl. This is my main work horse eyepiece. I use this eyepiece for >90% of my observing time. The reason it is my most used eyepiece is that it gives my telescopes the fastest possible “effective focal ratio” (which results in the brightest possible image at the eyepiece). In simple terms think of this eyepiece as being able to double the speed of your telescope (like a 0.5x reducer). I use this eyepiece for nebulae, galaxies & open clusters.

2.       Tele Vue 35mm Panoptic. I use this eyepiece occasionally when I want more magnification but still want a bright accelerated image (it acts like a 0.7x reducer for the effective focal ratio). An alternative to this eyepiece would be the Panoptic 41mm - I use the 35mm because it’s half the weight of the 41mm! I use this eyepiece for nebulas, galaxies, comets, large open clusters.

3.       Tele Vue Panoptic 27mm. I use this eyepiece again for greater magnification, usually for supernovae, globulars, comets & open clusters. I do not use this for nebulas and galaxies as the effective focal ratio is now too low and details are becoming lost at the eyepiece.

4.       Tele Vue DeLite 18.2mm. This is my least used eyepiece (as its focal length is smaller than the 26mm of the night vision device). In use, it has the effect of slowing my effective focal ratio and producing a dimmer image. It does however produce about the maximum useable magnification with my night vision a-focal setup and I have been successful using it for faint tiny supernovae and bright globular clusters.

NVeye.jpg.ac79e2dab1cf991a35ffc51fdcbdea0d.jpg

 

What about the huge exit pupils?

[Exit pupil is the width of the light beam being emitted from the top of the eyepiece and traditionally astronomers baulk at anything wider that the width of the astronomers own eye pupil as it is not possible for our eye to consume the whole of the light beam]

[Exit pupil is calculated as the eyepiece focal length divided by the telescope focal ratio so a 55mm Plossl in an f4 scope will produce a light beam 13.75mm wide]

As the night vision objective lens is 20mm wide then it can take all that light in and process it with room to spare! Whilst your eye pupil would be flooded and loads of light wasted, no light is wasted in this case.

But as the eyepiece focal lengths get shorter (and the exit pupils get smaller too), the night vision device soon starts to become starved of light.

 

How do I calculate this “eyepiece focal ratio” exactly?

Now seems the right time to show the maths to calculate the “effective” focal ratio of your telescope/night vision setup:

Effective focal ratio = NVD / (EPFL / TFR) where

        NVD = night vision device focal length = 26mm

        EPFL = eyepiece focal length

        TFR = telescope focal ratio

 

As an example, if we have a telescope with a focal ratio of f4, the 55mm Plossl will produce an “effective” focal ratio of f1.9.

[Effective focal ratio = 26/ (55/4)  =1.9] 

 

Does the focal ratio of my scope actually change?

The answer is NO. These changes in “effective” focal ratio that I mention only happen inside the night vision device. If your scope is f4 then it will remain f4.

 

Is a-focal observing, low magnification observing?

Simple answer = Yes it is. You need to get as much light as possible into the night vision device as fast as you can get it to go. All of the photons that you can get into the device will be amplified by the night vision device enabling you to see views containing previously unseen detail. In some cases, the amount of new detail on offer will be overwhelming!

At first, you will want to change eyepieces to achieve greater magnification but you soon discover that you actually see less detail (due to loss of effective focal ratio and exit pupil) so you soon return to the longer focal length eyepieces.

 

How do I calculate the magnification that each eyepiece will give me?

There is no change here. Take your telescope focal length and divide by eyepiece focal length.

If your scope has a focal length of 1800mm then you would get the following magnifications from my eyepiece set:

-          55mm Plossl (1800/55 = x33)

-          35mm Panoptic (1800/35 = x52)

-          27mm Panoptic (1800/27 = x67)

-          18.2mm DeLite (1800/18.2 = x99)

 

How do I calculate the TFOV?

I used Sky Safari for this. I setup my eyepieces in the “equipment” section using a setting of 40 degrees for the fov and it did the rest…

 

Can I use a coma corrector with night vision?

If your telescope has a fast focal ratio and you find that you need a coma corrector now then you will still need it for use with night vision. I used a Tele Vue Paracorr2 with my 20” dobsonian before I had night vision and I am still using it with Night Vision. In a big reflector, the best place for filters in the light path remains on the bottom of the Paracorr.

 

What about filters?

This brings us nicely onto every astronomers “favourite” topic – filters!

chroma1.jpg.cd72a3a3cf5d643bb5ef5a3759274b14.jpg

When combined with filters, night vision devices can allow us to not only see what was not visible before but also to steal back some darkness by blocking out our old enemy, the moon!

In the Cumbrian countryside, the night sky has an SQL of around 21.6, class 4 Bortle. Please take this into account when reading my experiences as your SQM may not be the same as mine.

1.     General observing For general observing, I do not use any filters as the best results are achieved by letting all the light into the night vision device. The PVS-14 has manual GAIN which means there is a knob that can be turned to decrease the gain and darken the image at the eyepiece – this is the only filter that I use in general observing.

        Moon – If the moon is up then I add a Baader 610nm Red filter into the light path. This is a good filter for reducing the effects of the moon on the sky background. It can also be effective if viewing low to the horizon where light pollution can be an issue.

2.     Filters for observing Nebulae

For nebulae viewing, a narrowband Ha filter in mandatory. I have tried 12nm, 6nm and 5nm and my preferred choice of bandwidth is the 5nm. As this filter is the “key” to seeing nebula then please do not scrimp of a “cheapie”. If you want to get the maximum from your expensive night vision device then only consider top brands such as Chroma, Astrodon, Astronomik or Baader.  I am currently using a Chroma 5nm Ha narrowband filter.

Your choice of Ha narrowband filter will directly affect whether you see some of the fainter nebulae objects or you do not see them!

3.      Filters for observing Galaxies

For galaxy viewing, there is no filter that can improve the unfiltered view. 
However, if the moon is up then I use either the Baader 610nm red filter or an Astronomik UHC Visual filter. If you are viewing tiny smudges then either are okay, if you are viewing larger galaxies with spiral arms, then I find that the Astronomik UHC Visual filter gives slightly more spiral arms than the 610nm red. Both beat unfiltered viewing if the moon is up.

@GavStar is using a “Baader IR pass” (685nm) filter from his city location for all non-Nebula targets to cut out the light pollution.

 

Which night vision units can I connect to my telescope for “a-focal” observing?

As a UK based astronomer there are very few options for us to purchase a Night Vision Device with the latest military specifications. The Tele Vue adapter works with the PVS-14 night vision device so this led me in that direction. 

I purchased my PVS-14 from www.actinblack.com based in Luxembourg.

Please do read my article on “Understanding Night Vision Tube Specs a little better” and do be prepared to wait a month or two for actinblack to get a new batch of tubes into stock (from which you can then pick the best one for astronomy use). I had to wait two months for a new batch of Photonis tubes to come into stock before I was sent three tube specification sheets to choose from via email.

Having selected my tube then it was delivered to me in under a week from placing the order.

act.jpg.70c31b64ee07dc9c0a0b752c18ef6c44.jpg

 

Which telescope do I need for Night Vision?

This is a good question and one that will be debated long into the future. My opinion is that the best telescopes for a-focal night vision use are telescopes with fast focal ratio.

I am using an f3.6 dobsonian and an f5.6 refractor.

Our goal is to achieve the brightest possible image at the eyepiece and focal ratio is the key to achieve that.

As we can see from above, there is a rather restricted set of eyepieces needed for night vision astronomy but if we pair these eyepieces with telescopes of varying focal lengths then we can get a wide range of actual field of views and magnifications. This drove my minimal set to two telescopes, one long focal length dobsonian with good aperture and largest possible magnifications (with long focal length eyepieces) and one short focal length refractor for wide field with decent apperture (> 4") and light enough for travel.

 

What can I see using Night Vision a-focally?

At this point, I want to point you to some of the many posts from @GavStar  available on this website. His images do reflect what I can see visually with my two setups.

Let me go on to summarize what I have been seeing in the last 17 months since the initial article.

Nebulae

I have now almost completed the full Sharpless catalog (303 of 313 objects). The only ones that I have not seen are the ones that are too low to my horizon!

Galaxies

I am working through the 200 brightest galaxies available in the skies above us. This project is more than half way complete and so far I have observed the spiral arms of 68 galaxies with direct vision.

Supernovae

Last year I viewed 17 supernovae, down to a magnitude of 16.8

Globular Clusters

I have so far failed to give sufficient time to Globulars, but their brightness means that I have been able to see some of the smallest and faintest on offer above us. I will get to these once my Galaxy project is completed.

Comets

Night Vision works well on comets, in a side-by-side test with traditional eyepieces, I saw better results with the night vision device.

Open Clusters

Night Vision gives great results with open clusters. The smallest ones just jump out at the eyepiece as you nudge around.

Planets

Failure – night vision is no good for planets. They are too bright.

Moon

Failure – night vision is no good for the moon. It is too bright.

Here are a few links to some of my reports (there are many more if you use the search facility)...

Do you still use eyepieces for observing?

My eyepiece case has been mostly sold off now. I have a set of short focal length DeLite eyepieces for planetary and I have some eyepiece pairs for solar observing with my Lunt LS60.

I use eyepieces to complete the 2-star alignments of my telescopes then it’s become automatic to just switch straight to the Tele Vue Plossl and my night vision to get into my nights observing. With the GAIN turned down it really is no different to using an eyepiece and you just see so much more…

 

Hope this helps somebody,

Alan

Edited by alanjgreen
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I would add that there is now a ‘prime’ night vision option for European astronomers, which wasn’t available when Alan and I got our night vision monoculars. 
Please see this thread:

 

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    • By alanjgreen
      Date: Friday 17th April 2020. 2320-0410hrs
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    • By alanjgreen
      Date: Wednesday 15th April 2020. 2300-0400hrs
      Scope: 20” f3.6 Lukehurst Dob with Paracorr (fl = 2089mm & f4.1).
      Night Vision: PVS-14 with Photonis 4g INTENS.
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    • By alanjgreen
      Equipment Used:
      Scope: 20” f3.6 Lukehurst Dob with Paracorr (fl = 2089mm & f4.1).
      Night Vision: PVS-14 with Photonis 4g INTENS.
      Eyepiece: Plossl 55mm (f2 x38).
       
      Background.
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      I have now completed a second pass through the grade 2 and grade 3 galaxies. This has resulted in some movement between bands based on my now greater experience and having a better idea of what I expect to see.
      My latest graded lists contain 38 grade 3 galaxies and 30 grade 2 galaxies (when combined this gives a list of the best galaxies to view when using military night vision technology combined with a low power eyepiece (using the TeleVue PVS-14 adapter).
      [Note that lower power eyepieces give the best spiral arm results as they “increase the effective focal ratio” of the telescope/night vision system which really helps increase the detail seen at the eyepiece.]
      As we are still in galaxy season 2020, now seemed a good time to re-publish my findings so others have the opportunity to observe some of these fantastic galaxies before they become “unavailable” for another 10 months…
       
      Grade 3 galaxies (the best of the best).
      M51 M61 M64 M65 M66 M81 M90 M91 M94 M95 M96 M99 M100 M101 M106 M109 NGC891 NGC2403 NGC2903 NGC3184 NGC3628 NGC3631 NGC3726 NGC3893 NGC3953 NGC4051 NGC4216 NGC4274 NGC4449 NGC4559 NGC4565 NGC4618 NGC4725 NGC5248 NGC5371 NGC5746 NGC5907 NGC6946  
      Grade 2 galaxies (good but the arms are not quite there…)
      M82 M88 M98 M104 NGC2537 NGC2768 NGC3294 NGC3344 NGC3373 NGC3596 NGC3646 NGC3675 NGC3718 NGC3729 NGC3813 NGC3938 NGC4013 NGC4214 NGC4293 NGC4389 NGC4490 NGC4517 NGC4535 NGC4625 NGC4762 NGC5005 NGC5364 NGC5383 NGC5775 NGC6015 Hopefully someone will find this useful information, next time they plan a galaxy observing session...
      Note that my dobsonian uses an Astrodevices Nexus unit which I control using Sky Safari. Here are my exported observing lists (which you can import into your Sky Safari app should you wish to do so?)
      Grade 3 Galaxies.skylist
      Grade 2 Galaxies.skylist
      1. email them to your phone/ipad,
      2. read the email on your mobile device and after clicking on the attachment, you should be offered the chance to “send to Sky Safari” by your email app…
      3.Sky Safari will open and give a message “Observing List Created”.
       
      Clear Skies,
      Alan
       
    • By alanjgreen
      Date: Friday 20th March 2020. 2300-0305hrs.
      Scope: 20” f3.6 Lukehurst Dob with Paracorr (fl = 2089mm & f4.1).
      Night Vision: PVS-14 with Photonis 4g INTENS.
      Eyepieces: Panoptic 27mm (f4 x77), DeLite 18.2mm (f5.8 x115).
       
      Introduction.
      Unbelievably, I just completed my third straight night outside observing Hickson Galaxy Groups and Supernovae. After months of thin gruel, I am beside myself although a little tired it must be said!
      Conditions last night were the best so far and my results improved as a result...
       
      Hicksons (3 new to me).
      I spent yesterday making an updated Sky Safari observing list. My aim was to edit the “full Hickson observing list”, remove all those that I have observed to produce a “To Do Hickson” observing list. I will add the steps taken to do this at the bottom of this report in case anyone is wondering how this is done?
      Hickson 54 – Sky Safari lists this as having one member IC700. I centred the target in the 27mm Eyepiece (with Night Vision device attached) and immediately saw a long thin edge-on galaxy patch. This thin line is in-fact made of 4 galaxies but I was unable to split the line on this occasion. Hickson 50 – (“The faintest Hickson” according to what I have read while doing research the last couple of days). It is also not present in Sky Safari when you search for “Hickson”! I used galaxy “PGC 2485269” to locate the correct area of sky to search for Hickson 50. As I look into the eyepiece a tiny double patch caught my eye straight away! With time, I got glimpses of a third patch to the right of the first two. I knew that I was looking for a pentagon shape of galaxies and there seemed to be a general faint glow in the area where all these galaxies are hiding. I waited but none of the others came into view.😀 Hickson 62 – Sky Safari has a major fail for several of the Hickson catalogue in that it shows them as having too many members (20+) in some cases. I nudged around the oversized Sky Safari search area and came upon a patch of three tiny galaxies, checking my Ipad Sky Safari showed NGC4761, NGC4759, NGC4764 and some research this morning confirms these findings.😀 I came upon a great website detailing the Hickson galaxy group members:
      https://translate.google.com/translate?hl=en&sl=de&u=http://www.deepsky-visuell.de/Projekte/HCG34_66.htm&prev=search
      This information is really useful and I thank the author for publishing this data for me to find!😀
       
      Supernovae (6 from 7 attempted).
      Okay, onto the main diet for the evening…
      IC738/SN2020vg - SUCCESS. Repeating my observation from the previous night, the galaxy was once again tough to find. Once you have it then the elongated core can be seen within with the 18.2mm eyepiece. Images don't show a split so I am marking this one as a success.  PGC 041887/SN2020cdm – SUCCESS. I located the galaxy successfully in the 35mm, 27mm and 18.2mm eyepieces. It is located to the right of a small, mid-brightness “Xmas tree” star formation. A small patch is easily seen. Then it’s a case of letting the patch drift across the fov many times and watch for activity within using averted vision. With the 18.2mm eyepiece I was able to get 3 of 4 glimpses of a dot within the galaxy patch. NGC5371/SN2020bio – FAIL. I spent a long time on this large side-on galaxy but there was no sign of the Supernova in any eyepiece. I even tried an Ethos 10mm (conventional eyeball viewing) for greater magnification but the SN was not seen. I now doubt my observation from 18 March too. UGC9945/SN2019zhs – SUCCESS. With the 27mm eyepiece I quickly found the galaxy and could see the core within. Using the 18.2mm eyepiece I got occasional glimpses of two dots within the galaxy disk. PGC056547/SN2020dxa – SUCCESS. This is an easy target and it was nice after the work I had to put in on some of the previous ones! With the 18.2mm two dots within a dust patch are easily seen. UGC10661/SN2020awa – SUCCESS. The galaxy sits within a small triangle of stars (one corner of the triangle has 2 stars). With the 18.2mm eyepiece I could make out a dot within. PGC062161/SN2020duu – SUCCESS. This is another fairly easy one. It took a bit of time to find the edge-on galaxy. But once you have it there is a clear dot on the leading edge as it drifts across the fov.  
      Conclusions.
      After having two nights of not much sleep, I needed to pace myself last night. I delayed going out until 2300hrs so as to be able to stay out later without getting tired too soon. I am pleased to say that it was also warmer last night than the previous two nights (when I had to wipe of ice from the scope before packing away for the night).
      Perseverance is key with supernovae, you need to try them a few times to get the “lay of the land”. It’s amazing how you become familiar with the star patterns in the fov of the supernova’s parent galaxy. It’s like visiting an old friend by the third night. But it takes patience and concentration to get the faintest targets to pop into view and I was pretty tired by the time I packed up just after 3am.
       
      Clear Skies,
      Alan
       
      How to edit a Sky Safari observing list using Ipad & PC.
      Search for “Hickson” in Sky Safari Scroll to bottom of list and choose “create observing list” Use search to open the new observing list and scroll down to the bottom and choose “email observing list” On your PC, save the email attachment to desktop and add “.txt” to the end of the filename Edit the file with Notepad. Remove unwanted objects and save the file Remove “.txt” from the filename and email the file back to your Ipad On the Ipad, choose the email attachment and then choose “Sky Safari” when it asks what app you want to open the attachment with...
    • By alanjgreen
      Date: Sunday 1st March 2020. (2240-0220am)
      Scope: 20” f3.6 Lukehurst Dob with Paracorr (fl = 2089mm & f4.1).
      Night Vision: PVS-14 with Photonis 4g INTENS.
      Eyepieces: Plossl 55mm (f2 x38), Panoptic 35mm (f3 x60), Panoptic 27mm (f4 x77), DeLite 18.2mm (f5.8 x115).
      Filters: Baader 610nm Red Filter
      Moon: 39%
       
      Introduction.
      Wow, it’s already March and I’ve just completed my first real session of any note in 2020! The weather in the UK has been pants since Christmas. I have managed a couple of two hour dashes between the clouds but that is not enough time to really get into a session and do any real observing on any more than a few objects so I have mainly been observing the more famous and brightest night sky objects.
       
      Galaxy season is here!
      Yay, my favourite observing season is here. With all this down time, I at least had an observing plan to follow when the opportunity finally came. I had created observing lists in Sky Safari of the Hickson and ARP catalogs.
       
      Making a start on the Hickson catalog with Night Vision.
      There was a 39% moon in the West so I had to deploy a Baader 610nm Red filter to the front of my Paracorr2 to remove the unwanted moonlight from my view.
      On the first object, I tested out all the eyepieces listed above to see which produced the “best” view. There is a trade-off with night vision devices of image brightness and image magnification and I wanted to identify the best eyepiece option up-front as I intended to attach my eyepiece heater tape and then stick with the one eyepiece for the session.
      I settled on the Panoptic 35mm as my chosen eyepiece as it was giving decent image brightness resulting in more galaxy halo and the magnification (x60) was enough to provide something to see from these tiny objects.
       
      Hickson 37 – I could see three galaxies in a row close to two field stars. One galaxy was a longer edge-on and one had a bright core with faint halo. I found the fourth group member nearby just the other side of a field star although this one was a challenge to hold in vision for long. The final galaxy was glimpses occasionally with a real effort and concentration needed.
      Hickson 44 – Two small bright galaxies were immediately obvious, I soon located a third slightly separated galaxy of mid-brightness out in front. The final galaxy was the faintest of the four and was sited at 90 degrees to the side. All four galaxies were easily seen in direct vision.
      Hickson 46 – This group was hard to locate initially then I spotted two cores appearing close together in the field of view. After letting my eye settle in the other two galaxies appeared one on either side of the first two.
      Hickson 47 – Two cores were immediately obvious in the fov then one more emerged lower (near a field star). I did get glimpses of the fourth member which was in close to the third galaxy staggered to one side.
      Hickson 38 – Another group that was tough to find. Found just above left of two bright stars. Time reveals three galaxies in a triangle formation. The lower galaxy was the easiest with a nice halo. The upper two were smaller and fainter.
      Hickson 36 – The toughest so far! I found a possible very faint patch just below 6 stars. It looked like two groups of three galaxies but looking at images this morning then this looks incorrect so this goes down as a fail.
      Hickson 35 – Found inside a triangle of field stars. Three galaxies easily seen in a flat triangle formation. There was a possible fourth galaxy glimpsed to the left which was fainter.
      Hickson 41 – Two galaxies easily seen (one has a core and halo). The third was tough and appeared just under the fainter of the first two. No sign of the fourth member.
      Hickson 60 – A small patch is easily seen in the fov. One core dot is seen within the patch off–centre.
      Hickson 56 – This tiny group is located next to two much larger and brighter galaxies (NGC 3718, 3729) that overpower your vision as you reach the eyepiece. Once I was settled on my actual target then I saw two tiny bright galaxies first. Then the third was seen slightly separated to the RHS. Then one appeared LHS fainter giving a 3+1 appearance to the group.
      Hickson 55 – The small patch was quickly located in the fov. I could see two dot cores appearing on and off within the patch but not much more.
      Hickson 49 – not found.
      Hickson 61 (Box Galaxies) – A nice sight. Three bright galaxies make up three corners of the “box”. A fainter larger galaxy sits at the other corner. The two brightest galaxies were at the top side. The bright lower galaxy has a halo.
      Hickson 51 – Five galaxies are easily seen in the fov, appearing as 3+2. The galaxies appeared well spaced but were small.
      Hickson 57 (Copeland Septet) – A very nice galaxy group! I could see 7 galaxies appearing as 3+3+1 formation. All easily seen.
      Hickson 53 – I saw three galaxies in the fov in a 1+2 formation. The fourth member (off to the right) was not seen.
      Hickson 52 – Two galaxies were easily seen. Another galaxy is glimpsed intermittently near to the second galaxy with time at the eyepiece.
      Hickson 59 – 3 of 5 galaxies seen. Two are bright and easily seen. The third appeared at a right angle to the first two with the gain turned up.
      Hickson 58 – Four galaxies are easily seen in a 2+2 formation. The fifth needed further exploration but clouds starting passing and my session was cut off in its prime!
       
      Epilogue
      I make that 18 Hicksons attempted last night which seems like a good start and I am pleased with that.
      Most of the observations were taken with the Moon up so it will be interesting to try them again on a new moon to see if more can be seen…
      It was great to be back outside after nearly two months of slim pickings!
       
      Clear Skies,
      Alan
       
       
      Some Technical Background (Voluntary reading!).
      This section is added for anyone wondering why I was only using x60 magnification with my setup and maybe “more would be seen with greater magnification?”.
      While that would be true with traditional observing, night vision is best used with eyepieces with large exit pupils as the more light you get into the device then the more light it has to work with. Longer focal length eyepieces (greater than 27mm) also have a side-effect of increasing the effective focal ratio of your telescope system (as far as the attached night vision device is concerned) and as the NVD works at f1.2 then the closer we can get to that speed the better the results will be.
      So the facts are that the 55mm Plossl with always show the brightest view possible with the most galaxy details possible seen within that view.
      But when tiny objects are tightly packed then you may need more magnification to separate them (this is usually true for supernovae hunting for example).
      But as you increase magnification and decrease the exit pupil/effective focal ratio of the system then galaxy detail will be lost from the view. I only ever view galaxies where I hope to see the spiral arms with the 55mm Plossl as I want maximum brightness and fastest effective focal ratio.
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