Brightness of Horsehead nebulosity?

[tomato]

2 hours ago, John said:

 

I'm no imager but I'm told that the Horsehead is relatively easy to image and is quite straightforward with an EAA setup.  

These days it is indeed relatively straightforward to image the Horsehead, especially with the sensitive CMOS sensors.

But back in the film emulsion days it was a real challenge to photograph. I was elated to capture it on a 15 minute exposure from a proper dark sky location.

[scarp15]

Exit Pupil; this has been a hot topic of conversation in its own right, on many threads over the years that I have, at least, been involved with SGL when the Horsehead Nebula has been the particular subject of debate. 

General consensus is that with a moderate sized aperture telescope; a focal length eyepiece that provides between 4mm - 5mm exit pupil, creates a good balance between required contrast and image scale (coupled to a H-beta filter). 

A typical favourite amongst deep sky observers has been a Tele Vue 25mm Plossl (referred to as the magic eyepiece or magic exit pupil) and  / or Tele Vue 20mm Plossl, providing an optimum exit pupil in many focal length scopes and a narrow TFOV for keeping Alnitak out of view. 

Of course with a larger aperture dob  / scope, under favourable conditions, the magnification can increase (reports of 13mm Ethos being the weapon of choice in i.e. 18" dob) and the horsehead will simply 'pop' (no ifs, no buts).

Lets also keep talking about IC 434, I haven't really focused attention on this (too washed out), Mike has referred to it and I know that Gerry to has had success with this within his Canadian wilderness skies and there is much chatter on Cloudy Nights for example. For all committed preparations, our eyesights do differ though.

Here is a thread that I'd started when finding my way with other still familiar members on here, from quite a few years ago, when the feverish journey to 'bag' the Horsehead was (for me and others) in its infancy. I do miss aceys contributions.

It is ironic that one of the most talked about subjects on here, concerns the most substantial almost nothingness, in traditional observing terms.

Night Vision from a suburban back garden is the natural alternative of course if you have £££££ - yet the elusive 'thumbprint' would lose some of its hard earned legendary mystic.

Just one final point, once detected and familiarity is gained, I think that it is worth playing around with other eyepieces / exit pupils and scopes of varying aperture perhaps, so long as under the darkest, transparent moonless skies possible.

   

 

[bomberbaz]

I can't remember who gave me this map/guide to spotting it but I found it very useful.

I didn't use it at the eyepiece but studied it quite a lot in the days running up to my planned visit to galloway to get into my mind what I was looking for and more importantly, where I was looking for it.