Subject:Orion Optics Europa 250mm F4.8
Date:2003-08-06
Rev:0.1
Aperture = 250mm
Focal Length = 1200mm
Focal Ratio = f4.8
Tube Length = 1138mm
Tube Weight = 8kg
Finder = 6x30
Faintest Star = 14.5 Mag
Resolution = 0.46 Secs
Focus Mount = 31.7mm
Having used a TAL100R for a few weeks before i received the Europa i set the tripod up in the garden during daylight hours at full height. My wordy was that a mistake, the focuser well above my viewing height. Not by just a little but by a clear meter or so. I lowered the tripod legs to the minimum height and still when looking at the Zenith I, a six foot 3 inch tower needed a box or chair to stand on. Anyway all that means is i will have to plan my observing sessions a little before i start.
As with the Meade the first thing i pointed the scope at was the Moon. It didn't really look that much different to the view with the Meade untill i changed from a 25mm eyepiece to the smallest i have, a 6.5mm. With the Meade the image would have broken down to a practically unusable image. With the Europa it was crystal clear. More detail than i have ever seen, this is straight out of the box (which was not packed that well) with no collimation. Secondly i turned to an old astronomers favourite Alberio (500k). Again with no collimation the view was greatly improved on anything i had seen before even at low magnifications (100x 12.5mm EP). The distance angle was clearly pronounced and the colours where more vivid. The third target was the globular cluster M13 in Hercules. Having only ever seen this object as a fuzzy patch with a dotted with a few stars on the fringe i was shocked to see thousands of point sources with a 25mm EP. My word this scope is powerful.
With the recent rise of Mars on it closest approach for all of humanity i was let down by the Europa. Given the size and cost of the scope the planetary performance was not anywhere near as good as i expected. The Tal outperforms the Europa by 5 fold for a scope with 150mm less aperture. I tried collimation but because i have never seen down the barrel of a correctly collimated newt i will never know if it is correct. I can see in the observing session after collimation that star focus is greatly improved but planetary performance still lacks (in my view). Having said that, what the Europa lacks in planetary performance it more than makes up for in deep sky and cluster(my favourites) performance. Clusters such as M71, M22, M92 ,M13, M9, M107 and M12 all contain visible point sources and Nebulae are now viewed with fine grain and colour compared to the Meades grey blobs of light.
Although this makes these faint fluffies harder to see it does bring a new world of detail to viewing such objects. The one object i am still unable to find is M101, for months i have tried with both the Meade and the TAL to no avail. After doing my first proper accurate polar alignment with the EQ-6 i decided it would be time to try and use the setting circles to find this illusive object. Check Ceil for the coords RA only for now, turn the RA axis to the correct reading and there she blows. Using a 40mm EP i can barely see the object. I use slow motion controls to center the object then change up to a 25mm EP now i can start to see the spiral arms of this galaxy but the detail is very fine and when my other half switches on the kitchen light to make a cup of tea it disappears from view. Upon my return and re-dark adaption i continue to view the object and up to a 12.5mm EP at which point the image starts to degrade and i also realise that it does not fit into the field of view. This telescope is excellent for this kind of work giving a crystal clear image even under relatively bad atmospheric conditions.
I have made a couple of attempts at taking pictures with this scope and one of the results can be found on the latest astro image page. Along with M13 i have also imaged M57 but stacking those images is proving quite difficult. I have also tried some piggy back photography with a 300mm FL lens, to my dismay out of a 24exp film i only got 5 good pictures due to an incident with the power lead for the mount. See the EQ-6 page for details. I will continue to practice taking both piggyback and afocal pics with this scope and post the results here when i get some good ones.
Altogether after a decent collimation (not sure if i am actually pulling off a decent collimation yet) this scope is worth every penny. With its fast focal ratio it is an excellent scope for photography and visual observations alike. Yes it is large and it does take a bit of getting used to, even for a tall bloke like me. I am glad i bought this scope as my setup now has the best of both worlds, a small refractor for planetary work and a large reflector for faint fluffies. All i desire now is a 2x barlow (maybe my nice girlfriend will get me one for xmas) so i can push the magnification up to 250x+. The clarity of image on nebulae, GC's and OC's is outstanding, the planetary performance is not as good as i expected but even so it is adequate.
Ah ha, i have, at last had the bottle to take the mirror out of the scope and put a square of tape in the center of it to "help" me collimate the scope. Upon reassembly cocollocationllomation began. Im not going into details because quite simply, it didnt work. The biggest problem i am having is not knowing what the view down the focuser should look like. Anyway like i said it was wrong, better luck next time.
Although i know the scope is out the image quality is still pretty good, although trying to focus on a star is practically impossible.
This time i decided to take a different approach, instead of concentrating on the "dot" in the middle of the primary. I simply turned the secondary untill the whole primary was visible then adjusted the primary. Looking down the tube now shows nice neat concentric circles of tube, primary, secondary, focuser tube, eye. Hopefully that is done and all that will be needed now is a touch of tweaking at the start of my next observing session.
Magic, i finally seemed to have cracked the collimation bug and the scope seems to perform very well, now all i have to do is pluck up the courage to strip the scope and clean the mirror..
Application
Having read a few documents about the advantages and disadvantages of flocking reflectors i decided i would give it a go.
I bought some evostick and some cheap felt from C&H Fabrics and stripped the
scope down to a tube. Firstly i checked the adhesive by applying it to a shiny tobacco tin lid(the scope tube is matt). It
stuck, not as securely as i would have liked but it stuck none the less. I didn't really know how to start, i know i could
not apply the flock to the entire tube in one go so i opted for applying a section at a time. I cut 5 strips of flock and
began applying the evostick. At this point i should mention those who have no experience with mind altering drugs(LSD,
Magic mushrooms and the like) should probably do the gluing outside in a well ventilated area! I, on the other hand have
had such experiences and found the effects of the fumes from the glue quite enlightening, as did my chosen assistant ;)...
Seriously though, the glue tin says that it is dangerous to use in an enclosed space(like my dining room!) so unless you
want to be hot and cold rushing, dizzy, unable to speak and have narrowed vision, do it outside!!!!
Now, i apply the glue to a section of the tube approximately 1 or 2 inches larger then the actual flock, between the two of us we came up with the idea of rolling the flock around a broom handle then synchronously unrolling with one person at each end of the tube. Im sure(if we where not still under the influence of the glue fumes) this is a good plan, but given our state of minds it proved quite difficult to actually do things in sync. The process continued for about 2 hours with rhythmical communications ability completely breaking down for 10 to 15 minutes after every application of evostick. Once completed i allowed the scope to dry overnight in the comfort of my warm dining room. Upon awakening in the morning i found my youngest child(Tommy(1)) laying in the tube with my 4yo daughter(Kathrine) rolling him around the dining room to both their enjoyments.
The Results
The main trouble i had when trying to compare results is quite simply the time between uses of the scope. I used the scope, then
it was most likely a month before i flocked the scope and then a good 2 or 3 weeks until i got the chance to use the scope again!
Having typed that i do belive there is a great improvement in contrast and maybe(maybe not) sharpness(focus?) of image. Planetary
work, especially the Moon seems to be very much brighter. OC and GC performance does not seem to be any better but i did notice a
great deal of improvement in the outer edges of M31, especially at low magnifications... Altogether for 20 quid and a few hours of
stripping scope, applying glue and flock then re-assembling its well worth the bother. I would recommend this to anyone who is trying
to improve any scope be it a good quality one such as a Europa or a bit box home made jobbie..
Cost: £22.75
First i marked out the square of the fan then found a circular object about the same size as the circular area of the fan, in this case a cup! Secondly i used a small steel rule to mark a set of boxes on the circle, do this simply by lining the rule up to the last line. At the cross sections where there was enough room for a 12mm hole i center punched then piloted a hole to 4mm. Finaly i drilled the 4mm holes out to 12mm, punched and drilled the fan mounting screws along with another 4mm hole for the fan wires to run through.
Now i used a square to mark out 1 hole at one end 2 holes in the other end and one in the side of project. 3 holes for power supply/outlet and one for the switch. At this stage i also drilled out the bottom of the project box with 2 diagonaly opposed 4mm holes for attaching the box to the back plate of the scope. Now with all my holes drilled i carefully sanded all the terminals i intended to solder to such that the solder would stick. Once done i installed all the sockets and the switch into the box. Now everything is installed it is time to do the solder in the wires.
Unfortunately i could not actually work out how to do the wiring without drawing a little danny diagram to explain to myself how the power would flow around the box. I wanted to wire it such that it did not matter which socket i plug the power into. I did however base my diagram on using the single socket for simplicity. I chose the single socket to which i soldered 3 wires on the positive(inside of the headphone plug), one for the power to the fan switch, the other 2 to feed the remaining sockets. Then i repeated the procees for negative but i only used 2 wires this time, one for each outlet. I soldered the positive connection for the fan to the other side of the switch and the negative to the negative terminal of the power inlet. I have yet to try different sockets for power feed. I am unsure as to wether or not the power will be the correct for the fan, it should be!
Now all the wires are firmly attached all that is left is to attach the box to the scope back plate. A simple job!
Although i have yet had chance to test the effect of the fan i do know that the scope used to take about 90 minutes to cool to ambient temperature. The scope is stored as close to outside temperature as i dare without actually putting it outside so i guess maybe 3 or 4 degree F higher than ambient temperature. I am hoping to see cooling times reduced by about 40 to 60 minutes with the fan pulling 25 CFM of air through the scope. This changes the air in the tube once every 3 or 4 minutes.