kkokkolis

Προχώρει, σε παρακολουθούμε με τρομερό ενδιαφέρον.

Και εγώ με την κεντρική παλεύω συνήθως. Το μικρό εμβαδόν του δευτερεύοντος δεν αφήνει περιθώρια για σφάλματα.

Αυτό που λέει ο φίλος μας Κώστα είναι πως τα έσω στεφάνια είναι διαφορετικά από τα έξω, αφού είναι έτσι διαμορφωμένα ώστε να χειρίζονται τους πόλους. Τα απλά από ένα τηλεσκόπιο ενιαίου σωλήνα χωρίς μετατροπή δεν θα λειτουργήσουν. Βλέπεις εδώ: Στο άνω έσω τμήμα υπάρχουν τρεις προεκτάσεις όπου πιάνουν σταθερά οι πόλοι και άλλες τρείς στην κάτω έσω στεφάνη, μέσα στις οπές των οποίων σύρονται και σταθεροποιούνται με μία βίδα- φρένο. Αυτά είναι χυτευμένα στην στεφάνη για να εξασφαλίζεται ακαμψία και δεν υπάρχει τζόγος, εξ ου και διατηρείται άψογη η ευθυγράμμιση. Που θα βρεις τέτοια στεφάνια; Μπορείς να τα φτιάξεις με κάποιον τρόπο;

Τελικά μήπως κακώς επενδύουμε σε εξοπλισμό για ένα χόμπυ που φαίνεται καταδικασμένο να πεθάνει;

Astronomy Hacks, Robert Bruce Thompson, Barbara Fritchman Thompson, 2005 Κάποιοι θα έχετε αυτό το σημαντικότατο βιβλίο. Ακόμη περισσότεροι ίσως συναντήσατε μια πειρατική εκδοχή του. Τώρα μπορείτε να το διαβάσετε νομίμως (το μεγαλύτερο μέρος του τουλάχιστον) ως δωρεάν eBook από εδώ: http://flylib.com/books/en/3.311.1.1/1/ Με περιορισμένα δικαιώματα, πάντως θεωρώ πολύ σημαντικό να διαβαστεί ειδικά από τους αρχαρίους.

Μπράβο! Τα στεφάνια που τα βρήκες; Και, αλήθεια, γιατί η αράχνη περνά από τον άξονα δευτερεύοντος- εστιαστή; Έτσι βλέπω πως τα φτιάχνουν, αλλά γιατί; Σε αντισυμβατικές αράχνες παρακάμπτουν τον άξονα: Σε DIY προτείνεται το ίδιο:

Και στο φεγγάρι εξέχει.

Αν έχει κάποιος την καλοσύνη ας καταγράψει μια-δυό από τις καλές μαντινάδες.

Επειδή η μεγέθυνση δεν είναι και τόσο μεγάλη, μπορείς να χρησιμοποιήσεις τον Barlow και να έχεις το σχετικά καλό eye relief σε μεγέθυνση 240x. Με τον Powermate δεν βλέπω πτώση στην ποιότητα.

Η μεθοδολογία του allbinos.com Description of test methods and categories. TRANSMISSION (15 points) - Currently we use spectophotometer to obtain the transmission graph in the range of wavelenghts from 380 to 900 nm. The method is very precise one and allows us to minimalize uncertainties to around 1%. In older tests we used three less accurate methods: We mount a high level digital camera to an eyepiece (ocular lens) and we take a picture of diode. Then after standard procedure of data reduction, we carry out aperture photometry by comparing diode brightnesses (measured by eyepiece + camera configuration). Results depend only on lens diameter (which we know) and light transmission (which we can count). We mount a high class CCTV video camera and record diverse luminosity star clusters (for example ‘Pleiades’) on a very starlit sky. The differences in range results from different transmission. Another method rests on projecting intensive sunlight onto shaded white screen. A part of this screen is directly sunlit and to shaded part we glue a ruler. The screen is located in a specific distance to line up and cover screen surface brightness with projected image of sunlight surface brightness. Now we take a picture of this projected image of sun by camera. The ruler let us measure the scale of taken picture. A proportion of measured sun image in relation to actual lens area gives us the transmission. By doing many measurements and using independent methods, we estimate the precision of transmission estimate in range of 3-5%. CHROMATIC ABERRATION (10 points) - The chromatic aberration is estimated by our own observations, setting a contrastive object in the center of the field of view and moving it to the corner. Depending on our observations, binoculars can get here from 0 to 8 points for the center performance and -/+ 2 points for behavior at the egde. ASTIGMATISM (10 points) - We considered a level of astigmatism trying to achieve a perfect punctual image of stars. Then focusing in two different distances we measured the vertical and horizontal deformation in relation to spherical symmetry axis. DISTORTION (10 ppints) - We arrange binoculars in opposite to the wall where we previously hung a graph paper. Several testers personally determine field of view tested binoculars and consider which line (from the central point) seem to be curved. Results are given in percent proportionally in relation to field of view radius. COMA (10 points) - It is a spherical aberration referring to distortion of rays running through the lens at the corners. It deforms image of stars which look like V letter or appear to have a cometary coma, hence the name – coma. We measured it by moving the stars to the corners of binoculars field of view and estimated the size of the deformation and how far from the center it appears. BLURRING AT THE EDGE OF FOV (10 points) - We arrange binoculars in opposite to the wall where we previously hung a lightened graph paper. Several testers personally determine field of view tested binoculars and focusing binoculars at the central field of view. Then starting from the central, most sharp point and moving to the corners they consider where on graph paper lines start to get fuzzy and blur. EYEPIECES FOV (10 points) - We multiply an actual magnification by an actual field of view so that we could gain eyepieces apparent field of view. HOUSING (8 points) - We evaluated: what kind of materials have been applied, how do binoculars behave in use, is it comfortable and ergonomic gripping, do elements move smoothly and are there any squeaks or clearances especially in the area of the front lens. We also checked the eyepiece shell, if it is comfortable when put eye against ocular, and of course the general observation comfort. FIELD OF VIEW (8 points) - That is the test checking up the truthfulness of manufacturers. We arrange binoculars in distance from 6 to 15m in opposite to the graph paper. Several testers personally determined the field of view. Measurements were very precise that error of measurement was only about 0.02-0.04 degree. Afterwards we compared the actual results to manufacturers parameters. There were extra points possible to gain by an unusually large field of view – 2 points and additional 1 point for larger field of view than given by manufacturers. REAL FRONT LENS DIAMETER (8 points) - That’s the another test of manufacturers truthfulness. Several tester measured personally lens diameter by slide calliper. We averaged the results achieving precision on 0.05 mm level. Front lenses could gain 4 points per each. VIGNETTING AND PRISMS QUALITY (8 + 8 points) - We estimated how much gathering by lens light is wasted in too small or poorly arranged prisms. Does any mechanisms or internal instruments, supporting prisms, obstruct field of view? Are prisms made by Bk7 or BaK-4 glass and what is its quality? We measured the image of exit pupil using a digital camera and we measured precisely how much area of pupil is vignetting and dimness covered. WARRANTY (6 points) - Convention of rating was like this: 0p. for less than 1 year warranty, 1p. for 1 year warranty, 2p. for 2 years warranty, 3p. for 3-5 years warranty, 4p. for 5-10 years warranty, 5p. for 10-30 years warranty and 6p. for longer than 30years warranty. INTERPUPILARY DISTANCE (6 points) - The minimal and maximal interpupilary distance. It was rated as following: >=74mm – 5p., 73mm – 4p., 72mm – 3p., 71mm – 2p., 70mm – 1p., <=69mm – 0p. One extra point was possible to gain by minimal distance narrower than 50mm and one penal for minimal distance wider than 59mm. Maximum points to gain was 6. COLLIMATION (5 points) - Poor tubes adjustment may cause viewer headache. Collimation was checked by choosing (at the centre field of view) faraway point (star or lighthouse). Then we distance binoculars against our eyes for about 20cm. 5 points so the maximal rate was gained by binoculars where there was no splitting up of image. QUALITY OF THE INTERIOR OF THE BARRELS (5 points) - We evaluated quantity of dust and general impurity inside the binoculars by putting it against the glare light. We also evaluated materials quality intended for blackening the interior of binoculars and checked the quantity of glossy elements. INTERNAL REFLECTIONS (5 points) - Binoculars should be perfectly blackened inside. In addition the image of exit pupil should be clear on the black background, without any reflections. That’s why we took images of pupil in dark room (using always the same exposure time and lighting conditions) whereas the binoculars were directed towards bright and regularly lighten white wall. WHITENESS OF THE IMAGE (5 points) - We looked through every binoculars at white wall of building in the daylight and considered modifications of white color depended on given binoculars. FOCUSING (5 points) - We checked how smoothly the eyepieces move. We subtracted points for too stepping and irregular ocular moves and possibility of getting out of adjustment by pushing on oculars. Besides we subtracted points for defects like leaking or freezing on cold lubricant. DARKENING AT THE EDGE OF FOV (5 points) - All binoculars image quality is getting worse and worse when we move our sight to the edges field of view. The less intensive that effect is, the better binoculars are. Every tester personally checked transmission and quality on the edges by moving observing stars from centre to border field of view. ANTIREFLECTION COATINGS (5 points) - Quality of antireflection coatings on the air-glass border; what is quality? how many light is reflected? We lighted up by glare light and evaluated color and quality of reflections. REAL MAGINIFCATION (3 points) - The another manufacturers truthfulness test. We took pictures of open caliper which was put against pupil and checked is it the same as original parameters. We were able to measure exit pupil exact to 0.1mm. As far as we knew an actual lens diameter we gained the magnification exact to typical 0.2-0.3x measure error. CLOSEST FOCUSING DISTANCE (2 points) - Considering binoculars with 8-10x magnification we granted 2p. for 5 and less meters, 1p. for 5-6.5 meters and 0p. for distance longer than 6.5 meters. Considering binoculars with 15-20x magnification we granted 2p. for 8 and less meters, 1p. for 8-11 meters and 0p. for distance longer than 11 meters. How to understand the overall results of our tests? See a list below: 150 p. and more - perfection 140-149p. – outstanding result 130-139p. – excellent result 120-129p. – very good result 110-119p. – good result 100-109p. – middling result 90-99p. – not so good result 80-89p. – poor result 70-79p. – bad result under 70p. – pathetic result http://www.allbinos.com/2.1-article-How_do_we_test_binoculars_.html

Φαίνεται πως υπάρχουν αρκετές παραλλαγές του εν λόγω φακού Μάνο. Ο δικός μου ρίχνει σταθερό φως. Όποιος τον πετύχει θα δοκιμάσει φυσικά τον τρόπο λειτουργίας του. Το σώμα πάντως παραμένει το ίδιο και είναι από πλαστικό χαμηλής ποιότητας με μέτρια εφαρμογή.

Διεγράφη από τον δημοσιεύσαντα.

Βlue chair, polka dot walls, midnight stars and ocean beyond, Ιndependentman

Οι Energizer στα Super Market, δίπλα στις μπαταρίες. Οι υπόλοιποι σε καταστήματα ηλεκτρικών, τα Jumpo και κάποιους πάγκους πλανοδίων. Όπως βλέπεις εδώ, όποιον και να πάρεις με λίγο φίλτρο μετατρέπεται.

Midnight Moon and Stars Cupcakes, Daiane Militao, 2012 Να πάνε κάτω τα φαρμάκια!

Midnight Stars Snap-On Cover Αλλά ούτε και εκείνο- δίχως- το- οποίο- το- θηλυκό- του- ανθρώπου- δυστυχεί.

Midnight Stars Turtleneck Fleece Dog Pajamas, Klippo Αγαπητές μου κυρίες, επάνω στον ζήλο σας να ενδύσετε ευπρεπώς τους συμβίους, θου, μην αμελήσετε και τους καλύτερούς σας φίλους.

Midnight, Archibald Lampman From where I sit, I see the stars, And down the chilly floor The moon between the frozen bars Is glimmering dim and hoar. Without in many a peaked mound The glinting snowdrifts lie ; There is no voice or living sound; The embers slowly die. Yet some wild thing is in mine ear ; I hold my breath and hark ; Out of the depth I seem to hear A crying in the dark ; No sound of man or wife or child, No sound of beast that groans, Or of the wind that whistles wild, Or of the tree that moans : I know not what it is I hear ; I bend my head and hark : I cannot drive it from mine ear, That crying in the dark.

Τάσο, ανέσκαψα αυτόν τον φακό από το βάθος μιας εργαλειοθήκης όπου τον πέταξα όταν πήρα τον Energizer. Ο δικός μου είναι ολόιδιος αλλά έχει 3 κόκκινα LED (μάλλον τα είχα βάψει εγώ) και μια λυχνία πυρακτώσεως. Ανάβει κυκλικά, 1 LED, 3 LED, Λυχνία. Του έβαλα κόκκινο φίλτρο και 3 παράταιρες μπαταρίες. Φαίνεται να δουλεύει καλά τώρα. Τον έβαλα στο αστροντούλαπο για ώρα ανάγκης και θα τον δοκιμάσω το βράδυ. Το πρόβλημά του είναι πως έχει και μια οβελιαία λωρίδα την οποία βρίσκω ενοχλητική. Μη μου φαλάκρα τάρατε!

Ανανέωση. Έτοιμος να αγοράσω κάποιο εκ των: 1. ES82 30mm νεότερης σχεδίασης 2. TV Delos 10mm 3. TV Delos 6mm 4. Προέκταση 2" 36mm Σκέπτομαι και τους Pentax XW 10, 7 & 5. Οπότε μην διστάσετε να κάνετε μια προσφορά.

Ο Υπερίων 24 στο f/4.7 δεν αποδίδει άψογα. Ευτυχώς υπάρχει ο ES68 24, ισάξιος ή και καλύτερος του Panoptic σύμφωνα με πληροφορίες και σε καλή τιμή. Οι Hyperions 10 & 8 δεν έχουν τέτοιο πρόβλημα. Στις αγγελίες υπάρχει και ο ES82 8.8 και αξίζει.

Coma Berenices, MisfitSiren

Coma Berenices, Zomgsami

Coma Berenices, Andrej Mashkovtsev

Άλλες δυό δοκιμές http://astroguyz.com/2011/11/25/review-the-hooded-observing-vest-from-dark-sky-apparel/ http://www.fjastronomy.com/?page_id=1812