14 replies to this topic

[ion]

I like to go outside and look up at the sky at night
while standing with my head held high. I want that
same experience when there's a scope between me and
the cosmos. A real benefit of standing behind the scope
with straight optics is how natural it is to accurately
point. Dropping planets in the center FOV between
100-200x is dead easy.

Casually Tele Vue ing Saturn in the city straight up for
4 minutes at a time as it drifts through 100 degrees
of Ethos 13mm mated to NP101is by 2.5x Powermate 104x:



Are you a straight shooter too?

[Cotts]

Literally straight up?  Nu-uh.  Not unless you are lying flat on your back.

 

Dave

[Spikey131]

I think chiropractors like the idea

[TOMDEY]

Good approach - an added benefit is that it's 1% brighter. Every photon counts.    Tom

[PirateMike]

I did that once. I laid down flat on the ground, and behold, I fell fast into a deep sleep. When I woke up I quickly realized that I was already late for work. 

 

But yes, straight up is certainly better. 

 

 

Miguel   8-)

Edited by PirateMike, 23 June 2022 - 03:45 PM.

[gnowellsct]

That 2.5x Power Mate going to eat up them thar degrees, Ion.  --GN

[DLuders]

Some of these 90-degree Diagonals would work well.  

[eyespy]

Hi,

 

I think that Ion (OP) was viewing objects below about 45* (the planets) that are usually more accommodating to straight through viewing and in some respects, are sometimes easier to view than when using a diagonal. 

 

Doug.....

[ion]

Literally straight up?

This setup works well for watching moon or sunrise and the planets
come up to about 25 degrees, then I'll switch to a 60 or 90
degree diagonal depending on scope elevation. As for looking
straight up, when Saturn is at 25 degrees elevation and placed at
the top edge of Ethos 100 degree field, one does have to look
up to 75 degrees altitude to directly see the planet
 

That 2.5x Power Mate going to eat up them thar degrees, Ion.  --GN

AFAIK Powermates don't change the AFOV.

[Orion68]

Nope, not me.

 

Neither my back nor my neck works that way anymore. Like the idea though.

[Sketcher]

Back in the good old days, (if older photos and sketches are any indicator) refractors were often used straight-thru.  Image searches show Maria Mitchell, Percival Lowell, Australian comet hunter Bill Bradfield, etc. using or posing with diagonal-less refractors.  Several of Leslie Peltier's sketches in Starlight Nights show him with straight-thru refractors.  Then there are the earliest telescopic astronomers, Galileo, etc. all of whom made good use of straight-thru refractors.

 

When  I started out (1960's) I had read that star diagonals tended to reduce light-grasp and performance.  So, with my first refractor, I often set aside the diagonal in favor of straight-thru use -- even when observing near my zenith.

 

More recently, there's the Galileoscope (shown in my avatar).  That's a strictly straight-thru telescope that I've used to observe all manner of celestial objects -- with an absence of any "real" problems.  Though I did opt to lie down and use that telescope handheld when observing the North America and Veil Nebulae when they were very near my zenith.  For all other observations, my Galileoscope was used with the tripod/mount shown in my avatar image.

 

Right-Angle finders have only become popular quite recently.  Prior to their increased popularity people were doing just fine (or at least making do with) using their various flavors of straight-thru finders.

 

Most modern refractors, designed for visual use, are designed with the use of star diagonals in mind.  Nowadays, one will often need to purchase an extension before being able to use these telescopes straight through.  That being said, my 130mm apochromat (1995 vintage) came with a straight-thru extension.  Some time after purchasing my 152mm refractor I purchased a straight-thru extension for that telescope -- just because I didn't want to rule out its straight-thru use.

 

While I use my 130mm and 152mm refractors mostly with star diagonals, both have seen some straight-thru use.  When comet NEOWISE was near my North horizon, one of my observations of that comet was made with the 152mm refractor straight-thru.  I had started out with the star diagonal, but quickly thought:  "Why look to the side when I could just as (or perhaps even more) comfortably be looking straight-thru?"

 

In a recent Galileoscope thread the straight-thu vs. diagonal usage came up.  One person basically stated that they could not recommend that telescope because he (and his wife) suffered neck pains -- due to having to use the Galileoscope straight-thru.  But realistically, I think it's incorrect to assume that all other users will similarly end up with neck pains.  I suffered no neck pains, and I've made fairly extensive use of my straight-thru Galileoscope; observing, taking notes, and even taking the time to make sketches.  Then there's the long history of others using straight-thru refractors.  I've not heard of neck pains being a common issue among 18th and 19th century telescopic observers.

 

When it comes to objects near one's zenith; from most of our observing locations, if we observe on a different date, or at a different time of night we can "catch" the same object when it's at a more convenient altitude for straight-thru observation.

 

So, yeah, I'll sometimes use an astronomical refractor straight-thru.

 

That being said, there are things that one can do to make straight-thru use more comfortable, details such as eyepiece height, how one sits (or stands), paying attention to where (in relation to one's zenith) an object is located before deciding that "now" is the time to observe that object, etc.  But (with a bit of sarcasm in mind) I guess the typical visual user of astronomical refractors today are less capable than those in the past, less healthy, less determined, less innovative when it comes to problem solving, etc. than were their 18th and 19th century predecessors.

Edited by Sketcher, 24 June 2022 - 05:05 PM.

[daquad]

I think straight through is possibly more advantageous for lunar and planetary where the absence of a diagonal would mitigate scattering, although a good prism diagonal will suppress scattering.  For deep sky and doubles, I do not see any advantage to observing straight through; in fact, it can be a hindrance for lunar and planetary, because comfort at the eyepiece is important to observing those fleeting moments of good seeing.

 

Dom Q.

[bikerdib]

In my younger days, yes, I would observe through my refractors without a diagonal.  That was 45 to 48 years ago, not anymore. 

[Rutilus]

When I wore the clothes of a younger man, I did quite a bit of

straight through observing. Now in older age, it's just a memory of former

times of better health that will never return. 

[gnowellsct]

AFAIK Powermates don't change the AFOV.

I was thinking about TFOV